RNA-guided transcriptional regulation and methods of using the same for the treatment of back pain

ABSTRACT

Described herein are compositions and methods for treatment and prevention of low back pain. The compositions include vectors comprising nucleotide sequences encoding one or more CRISPR-Cas system guide RNAs and a RNA-directed nuclease. The methods include modulating expression of a gene in a cell using said compositions, introducing a CRISPR-Cas system into a cell comprising one or more vectors comprising said compositions, inducing site-specific DNA cleavage in a cell, and treating a subject having lower back pain, and lower back pain caused by degenerative disc disease using the compositions disclosed herein.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § of International Application No. PCT/US2016/038137, filed on Jun. 17, 2016, which claims the benefit of the filing date of U.S. Provisional Application 62/230,931, which was filed on Jun. 18, 2015. The content of these earlier filed applications is hereby incorporated by reference herein in its entirety.

STATEMENT REGARDING FEDERALLY FUNDED RESEARCH

This invention was made with government support under Grant Number AR068777 awarded by the National Institutes of Health. The government has certain rights in the invention.

INCORPORATION OF THE SEQUENCE LISTING

The present application contains a sequence listing that was submitted in ASCII format via EFS-Web concurrent with the filing of the application, containing the file name SL_21101_0331U2 which is 17,745 bytes in size, created on Dec. 4, 2017, and is herein incorporated by reference in its entirety pursuant to 37 C.F.R. § 1.52(e)(5).

BACKGROUND

Lower back pain (LBP) is the single leading cause of disability worldwide having a global lifetime prevalence of 38.9%. Degenerative disc disease (DDD) and associated pathologies are considered major contributors to LBP. The progression of DDD is associated with an inflammatory environment that includes the presence of inflammatory cytokines (e.g., TNF-α, IL-Iβ) in the intervertebral disc (IVD) that are active in the degenerative process and may sensitize pain-sensing nerve fibers in the IVD.

Although both surgical and non-surgical treatments for DDD-induced LBP are able to alleviate symptoms, they, however, fail to prevent the progression of disc degeneration, thus, LBP often returns after treatment. To effectively treat DDD-induced LBP on a long-term basis, therapeutic methods that can slow DDD progression and reduce the need for surgical intervention are needed. DDD and its progression have been associated with the action of inflammatory cytokines in the intervertebral disc (IVD) that signal the breakdown of the extracellular matrix through their respective receptors. Therefore a method for effectively slowing DDD progression that inhibits the catabolic signaling of these inflammatory cytokines in the IVD is also needed.

SUMMARY

Disclosed herein, are CRISPR-Cas systems comprising one or more vectors comprising: a) a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA), wherein the gRNA hybridizes with a target sequence of a DNA locus in a cell; and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein components a) and b) are located on the same or different vectors of the same system, wherein the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA locus; and wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4.

Disclosed herein, are vectors comprising promoters operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA); and regulatory elements operably linked to a nucleotide sequence encoding a RNA-directed nuclease; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods of modulating of genes in cells, the methods comprising: introducing into the cells a first nucleic acid encoding a guide RNA (gRNA), wherein the gRNA comprises a DNA-binding domain, wherein the nucleic acid is operably linked to a regulatory element, wherein the gRNA is complementary to a target nucleic acid sequence comprising the gene; introducing into the cell a second nucleic acid encoding a transcriptional regulator protein or domain that modulates the target nucleic acid expression, and comprises a gRNA-binding domain, wherein the second nucleic acid is operably linked to a regulatory element; and introducing into the cell a third nucleic acid encoding a deactivated nuclease Cas9 (dCas9) protein, wherein the third nucleic acid is operably linked to a regulatory element, wherein the dCas9 protein interacts with the gRNA and is fused to the transcriptional regulator protein; wherein the cell produces the gRNA that binds the dCas9 protein and the transcriptional regulator protein or domain fused to the DNA-binding domain; wherein the guide RNA and the dCas9 protein co-localize to the target nucleic acid sequence and wherein the transcriptional regulator protein or domain modulates expression of the gene; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods for introducing into a cell a CRISPR-Cas system comprising one or more vectors, the method comprising: a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA), wherein the gRNA hybridizes with a target sequence of a DNA molecule in a cell; a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein components a) and b) are located on the same or different vectors of the same system, wherein the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA molecule; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods for introducing into a cell a vector comprising: a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA); a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods of treating a subject having degenerative disc disease, the method comprising: (a) determining the subject has degenerative disc disease; and (b) administering to the subject a pharmaceutical composition comprising a nucleic acid sequence encoding a CRISPR-associated deactivated endonuclease and one or more guide RNAs, wherein the guide RNA is selected from the group listed in Table 2 and Table 4.

Other features and advantages of the present compositions and methods are illustrated in the description below, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-E show DRG neuron imaging. FIG. 1A is a representative calcium signal (ΔF/F) for a neuron firing in response to heat stimuli. DRG neurons were considered to have fired when the ΔF/F for the neuron exceeded the threshold level defined as the mean ΔF/F value at baseline plus three standard deviations. FIG. 1B shows calcium images of representative DRG neurons at baseline, immediately following heat application (FIG. 1C), at maximum response to heat stimuli (FIG. 1D), and return to baseline following stimuli (FIG. 1E).

FIGS. 2A-C show degenerative IVDs sensitize peripheral neurons to heating. FIG. 2A shows the firing response of rat DRG neurons as a function of temperature was fitted to a Boltzmann curve for the degenerative IVD conditioned media (n=5 patients), healthy IVD conditioned media (n=3) patients), and control media groups. The T50 (FIG. 2B) and maximum (FIG. 2C) generated from dose response curve fitting for the degenerative IVD conditioned media, healthy IVD conditioned media, and control media groups. *=p<0.05 when compared to the control media group for the same temperature. #=p<0.05 when compared to the healthy IVD conditioned media group for the same temperature.

FIGS. 3A-D show that IL-6 is the primary mediator of peripheral neuron sensitization in the degenerative IVD. FIG. 3A shows the mean Boltzmann curve fittings of neuron response to thermal stimuli for the control media, conditioned media plus IL-6 antibody, conditioned media, and conditioned media plus isotype control antibody groups. The maximum (FIG. 3B) and T50 (FIG. 3C.) generated from dose response curve fitting for the control media, conditioned media plus IL-6 antibody (20 μg/mL), conditioned media plus isotype control antibody (20 μg/mL), and conditioned media groups (n=5). FIG. 3D shows the percentage of DRG neurons firing in response to temperatures of 39° C. and 44° C. when exposed to conditioned media or conditioned media plus IL-6 antibody. FIG. 3A-C, Values are mean±standard deviations. N=5 for all groups tested. *=p<0.05 compared to the control media group at the same temperature. #=p<0.05 compared to the conditioned media plus IL-6 antibody group at the same temperature. FIG. 3D is table showing the values as a percentage of neurons firing in response to thermal stimuli. *=p<0.05 compared to the conditioned media plus IL-6 antibody group for the same patient at the same temperature.

FIG. 4 shows that AKAP mediates sensitization of DRG neurons to heating in the degenerative IVD. Values are the mean±standard deviations. *=p<0.01 compared to the control media group. #=p<0.01 when compared to the degenerative IVD conditioned media plus St-Ht31P group.

FIG. 5 shows degenerative IVD conditioned media and acidic pH synergistically enhance sensory neuron desensitization to heating and trigger spontaneous firing.

FIGS. 6A-G show epigenomic editing of AKAP 150 expression in DRG Neurons abolishes degenerative IVD induced neuron sensitization to heating. FIG. 6A shows CRISPR based epigenomic editing vectors contains sgRNAs that directs the dCas9 endonuclease fused with KRAB to the PAM binding sequence of the genomic DNA leading to the expression of KRAB. FIG. 6B shows gene expression occurs when chromatin is maintained in the euchromatin (open) configuration by acetylation of the H3K9 histones. Expression of KRAB recruits endogenous factors that replace acetylation of H3K9 with tri-methylation, maintaining chromatin in the heterochromatic state, silencing gene expression. FIG. 6C shows the vector map of CRISPR epigenome editing targeting the AKAP 150 gene. FIG. 6D shows epigenome editing of AKAP 150 expression in rat DRG neurons. FIG. 6E shows the mean Boltzman fit curves of neuron firing response to thermal stimuli for naïve neurons exposed to control media and naïve cells, AKAP epigenome edited cells and non-target epigenomically edited neurons exposed to degenerative IVD conditioned media. The T50 (FIG. 6F) and maximum response (FIG. 6G) generated from the dose response curve from naïve neurons exposed to control media and naïve cells, AKAP epigenome edited cells and non-target epigenomically edited neurons exposed to degenerative IVD conditioned media.

FIGS. 7A-D show the results of screening for efficient epigenome editing in HEK293T cells. FIG. 7A shows the lentiviral cassette demonstrating components of the epigenome editing system and how their expression is driven. FIG. 7B is a bar graph showing the screening of gRNAs for TNFR1 significantly downregulated by 4 gRNAs. FIG. 7C is a bar graph showing the screening of gRNAs for IL1R1 significantly downregulated by 2 gRNAs. (* denotes p<0.05 compared to nontarget control). FIG. 7D shows a fold change in NF-κB activity in response to TNF-α dosing in HEK293T cells with TNFR1 edit mediated by gRNA 1 (*=p<0.05 (TNFR1/IL1R1 Edit vs. Naïve), #=p<0.05 (TNF-α/IL-1β dose vs. no dose control)).

FIGS. 8A-B show lentiviral mediated gene and receptor signaling downregulation in hADMSCs. FIG. 8A shows TNFR1 and IL1R1 expression in hADMSCs post-transduction of epigenome editing system under the control of selected gRNAs. FIG. 8B shows changes in NF-kB activity post TNF-α/IL-1β dosing in epigenome edited hADMSCs which express the epigenome editing system with the most efficient guides for each receptor (*=p<0.05 (TNFR1/IL1R1 Edits vs. nontarget Edit), #=p<0.05 (TNF-α/IL-1β dose vs. no dose control)).

FIGS. 9A-F show cell proliferation and ECM deposition in 3D culture by epigenome edited cells in the presence of cytokines. FIGS. 9A and 9B show the cross sectional area of cell pellets in mm², cultured with or without TNF-α/IL-1β (n=6). FIGS. 9C and 9D show percent changes in DNA content relative to undosed control (n=4-5). FIG. 9E is a representative image of hADMSC pellets, demonstrating visible size differences between TNFR1/IL1R1 edit cells and non-target edit control under inflammatory conditions. FIG. 9F shows H&E staining of cell pellets visualizing relative ECM content show lighter ECM staining in dosed non-target edit cells but not in TNFR1/IL1R1 edited cells. (* denotes p<0.05 compared to dosed nontarget edit control).

FIGS. 10A-F show the results of quantification of GAG contents in pellet cultures that have undergone chondrogenic differentiation for 3 weeks with or without the presence of TNF-α/IL-1β. FIGS. 10A and 10B show GAG content per pellet (n=5). FIGS. 10C and 10D) show the amount of GAG released into media during culture (n=7-8). FIGS. 10E and 10F show the sum of GAG content that was released and within cell pellets (n=5). (*=p<0.05 relative to 0 ng/mL control, #=p<0.05 relative to dosed TNFR1 edited cells.)

FIGS. 11A-B show the ability of epigenome edited hADMSCS to suppress PBMC proliferation in coculture. FIG. 11A shows the fold change in proliferation relative to PBMCs alone demonstrate suppression of PBMC proliferation by all hADMSCs (n=4). FIG. 11B shows a representative flow cytometry graph of PBMCs demonstrating a visible decrease in CD45 EdU positive cells (graphs represent condition they are directly beneath in part A graph). (*=p<0.05 relative to PBMCs alone, #=p<0.05 relative to coculture with naïve hADMSCs.)

FIGS. 12A-B show knockdown of TNFR1 (A) and IL1R1 (B) with multiple promoter-targeting gRNAs (*=P<0.05 compared to non-target control).

FIGS. 13A-B show transduced primary human NP cells (A) expressing CRISPRi system as evidenced by GFP expression and the knockdown of TNFR1 in NP cells using TNFR1 CRISPRi lentiviral vector (B).

FIG. 14 shows the fold change in NF-KB activity by HEK293T cells dosed with TNF-α. Differences between the knockdown and the number of knockdown cells are statistically significant (P<0.05) for each dose as denoted by *.

FIG. 15 shows an example of a singleplex upregulation vector. The vector shown comprises dCas9-p300core.

FIG. 16 shows an example of a singleplex upregulation vector. The vector shown comprises dCas9-KRAB.

FIG. 17 shows an example of a multiplex upregulation vector. The vector shown comprises dCas9-p300core.

FIG. 18 shows an example of a multiplex upregulation vector. The vector shown comprises dCas9-KRAB.

DETAILED DESCRIPTION

Many modifications and other embodiments of the present disclosure set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the present disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Before the present compositions and methods are disclosed and described, it is to be understood that they are not limited to specific synthetic methods unless otherwise specified, or to particular reagents unless otherwise specified, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, example methods and materials are now described.

Moreover, it is to be understood that unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, and the number or type of aspects described in the specification.

All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present disclosure is not entitled to antedate such publication by virtue of prior disclosures. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

Definitions

As used in the specification and in the claims, the term “comprising” can include the aspects “consisting of” and “consisting essentially of” “Comprising can also mean “including but not limited to.”

As used in the specification and the appended claims, the singular forms “a,” “an” and “the” can include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a compound” includes mixtures of compounds; reference to “a pharmaceutical carrier” includes mixtures of two or more such carriers, and the like.

The word “or” as used herein means any one member of a particular list and also includes any combination of members of that list.

As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur and that the description includes instances where said event or circumstance occurs and instances where it does not.

As used herein, the term “sample” is meant a tissue or organ from a subject; a cell (either within a subject, taken directly from a subject, or a cell maintained in culture or from a cultured cell line); a cell lysate (or lysate fraction) or cell extract; or a solution containing one or more molecules derived from a cell or cellular material (e.g. a polypeptide or nucleic acid), which is assayed as described herein. A sample may also be any body fluid or excretion (for example, but not limited to, blood, urine, stool, saliva, tears, bile) that contains cells or cell components.

As used herein, the term “subject” refers to the target of administration, e.g., a human. Thus the subject of the disclosed methods can be a vertebrate, such as a mammal, a fish, a bird, a reptile, or an amphibian. The term “subject” also includes domesticated animals (e.g., cats, dogs, etc.), livestock (e.g., cattle, horses, pigs, sheep, goats, etc.), and laboratory animals (e.g., mouse, rabbit, rat, guinea pig, fruit fly, etc.). In one aspect, a subject is a mammal. In another aspect, a subject is a human. The term does not denote a particular age or sex. Thus, adult, child, adolescent and newborn subjects, as well as fetuses, whether male or female, are intended to be covered.

As used herein, the term “patient” refers to a subject afflicted with a disease or disorder. The term “patient” includes human and veterinary subjects. In some aspects of the disclosed methods, the “patient” has been diagnosed with a need for treatment for an infectious disease, such as, for example, prior to the administering step.

Ranges can be expressed herein as from “about” or “approximately” one particular value, and/or to “about” or “approximately” another particular value. When such a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” or “approximately,” it will be understood that the particular value forms a further aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint and independently of the other endpoint. It is also understood that there are a number of values disclosed herein and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. It is also understood that each unit between two particular units is also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

“Inhibit,” “inhibiting” and “inhibition” mean to diminish or decrease an activity, response, condition, disease, or other biological parameter. This can include, but is not limited to, the complete ablation of the activity, response, condition, or disease. This may also include, for example, a 10% inhibition or reduction in the activity, response, condition, or disease as compared to the native or control level. Thus, in an aspect, the inhibition or reduction can be a 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%, or any amount of reduction in between as compared to native or control levels. In an aspect, the inhibition or reduction is 10-20, 20-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, or 90-100% as compared to native or control levels. In an aspect, the inhibition or reduction is 0-25, 25-50, 50-75, or 75-100% as compared to native or control levels.

“Modulate”, “modulating” and “modulation” as used herein mean a change in activity or function or number. The change may be an increase or a decrease, an enhancement or an inhibition of the activity, function or number.

“Promote,” “promotion,” and “promoting” refer to an increase in an activity, response, condition, disease, or other biological parameter. This can include but is not limited to the initiation of the activity, response, condition, or disease. This may also include, for example, a 10% increase in the activity, response, condition, or disease as compared to the native or control level. Thus, in an aspect, the increase or promotion can be a 10, 20, 30, 40, 50, 60, 70, 80, 90, 100%, or more, or any amount of promotion in between compared to native or control levels. In an aspect, the increase or promotion is 10-20, 20-30, 30-40, 40-50, 50-60, 60-70, 70-80, 80-90, or 90-100% as compared to native or control levels. In an aspect, the increase or promotion is 0-25, 25-50, 50-75, or 75-100%, or more, such as 200, 300, 500, or 1000% more as compared to native or control levels. In an aspect, the increase or promotion can be greater than 100 percent as compared to native or control levels, such as 100, 150, 200, 250, 300, 350, 400, 450, 500% or more as compared to the native or control levels.

As used herein, the term “determining” can refer to measuring or ascertaining a quantity or an amount or a change in activity. For example, determining the amount of a disclosed polypeptide in a sample as used herein can refer to the steps that the skilled person would take to measure or ascertain some quantifiable value of the polypeptide in the sample. The art is familiar with the ways to measure an amount of the disclosed polypeptides and disclosed nucleotides in a sample.

The phrase “nucleic acid” as used herein refers to a naturally occurring or synthetic oligonucleotide or polynucleotide, whether DNA or RNA or a DNA-RNA hybrid, single-stranded or double-stranded, sense or antisense, which is capable of hybridization to a complementary nucleic acid by Watson-Crick base-pairing. Nucleic acids as disclosed herein can also include nucleotide analogs (e.g., BrdU), and non-phosphodiester internucleoside linkages (e.g., peptide nucleic acid or thiodiester linkages). In particular, nucleic acids can include, without limitation, DNA, RNA, cDNA, gDNA, ssDNA, dsDNA or any combination thereof.

As used herein, the term “complementary” refers to the ability of a nucleic acid to form hydrogen bond(s) with another nucleic acid sequence by either traditional Watson-Crick or other non-traditional types. A percent complementary indicates the percentage of residues in a nucleic acid molecule which can form hydrogen bonds (e.g., Wastson-Crick base pairing) with a second nucleic acid sequence (e.g., 5, 6, 7, 8, 9, 10 out of 10 being 50%, 60%, 70%, 80%, 90%, and 100% complementary).

As used herein, the term “vector” or “construct” refers to a nucleic acid sequence capable of transporting into a cell another nucleic acid to which the vector sequence has been linked. The term “expression vector” includes any vector, (e.g., a plasmid, cosmid or phage chromosome) containing a gene construct in a form suitable for expression by a cell (e.g., linked to a transcriptional control element or regulatory element). The terms “plasmid” and “vector” can be used interchangeably, as a plasmid is a commonly used form of vector. Moreover, this disclosure is intended to include other vectors which serve equivalent functions.

All publications and patent applications mentioned in the specification are indicative of the level of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, certain changes and modifications may be practiced within the scope of the appended claims.

Low back pain is the leading cause of disability worldwide[58], ranks third in disease burden according to disease adjusted life years[40], and generates a tremendous socio-economic cost [26]. Numerous factors have been associated with back pain, including degenerative disc disease, which is characterized by the breakdown of the intervertebral disc (IVD) extracellular matrix (ECM)[35,48], a loss of disc height[55], an inflammatory response [9,10,16,31,39,52,53,57], and altered innervation of the IVD[14,16,17]. Despite the observation of these changes in the degenerative IVD and hypotheses on the relationship of these changes to painful symptoms[18,28,34,47], the underlying mechanisms are not well understood and treatment strategies are limited. Described herein is a model that was developed to demonstrate the underlying sensitizing interactions between the degenerative disc and peripheral neurons and used to demonstrate targeted clustered regularly-interspaced palindromic repeat (CRISPR) epigenome editing to modulate these degenerative IVD induced sensitivities.

In the healthy IVD, neurons innervate the outer lamellae of the IVD and originate in the dorsal root ganglion (DRG). The majority of these neurons are nociceptive neurons expressing calcitonin gene-related peptide (CGRP)[2-4,29,43] and TRPV1[2,4,39,43]. In degenerative IVDs, the number of nociceptive neurons innervating the disc increases[25] and nociceptive neurons expressing CGRP[4,7] extend into typically aneural regions of the inner ΔF and NP[4,7,14,16,17,33]. Nociceptive neurons innervating the degenerative IVD are exposed to pathologically high levels of IL-6, TNF-α, and IL-1β[9,11,36,37,52] and to pathologically low pH levels[30]. TNF-α, IL-1β, and IL-6 have been demonstrated to sensitize nociceptive neurons to heating[41,42,45] and induce thermal hyperalgesia[1,15,44,45] in models of peripheral neuropathy. Additionally, acidic pH (e.g., 6.0-7.0) lowers the temperature threshold of TRPV1 and potentiates signaling through TRPV1[12]. As a result, the presence of multiple sensitizing factors in the degenerative IVD may trigger discogenic pain by sensitizing TRPV1 to stimuli that are non-painful in healthy patients. Described herein is an in vitro model developed to investigate these interactions and test CRISPR epigenome editing strategies in peripheral neurons to regulate these interactions.

CRISPR epigenome editing allows for stable, site-specific[56] epigenome modifications to modulate gene expression. Briefly, CRISPR-Cas9-based epigenome editing utilizes a nuclease-deficient Cas9 (dCas9) and a synthetic guide RNA to target specific DNA sequences[13,24,38]. The fusion of KRAB to dCas9 produces targeted H3K9 methylation[20,32,46,54], which can be used to regulate endogenous gene expression. Disclosed herein are compositions and methods for direct regulation of peripheral neuron sensitization via CRISPR epigenome editing to treat, for example, discogenic back pain symptoms. Using this technique, back pain may be treated by epigenome modifications of pain related genes in nociceptive neurons.

Disclosed herein are models developed to test the hypothesis that degenerative IVD conditions (e.g., inflammatory cytokines and acidic pH) can induce sensitization of nociceptive neurons to noxious stimuli and to demonstrate CRISPR epigenomic editing of nociceptive neurons as a potential discogenic back pain treatment by regulating the peripheral neuron response to these deleterious interactions. This study elucidates the synergistic effects of low pH and the IL-6/AKAP/TRPV1 pathway as responsible for degenerative IVD neuron sensitization and demonstrates epigenomic regulation of this pathway as a pain modulation strategy.

Low back pain (LBP) is a widespread problem, ranking first overall in years lived with disability (Murray and Lopez, 2013), and having an estimated global lifetime prevalence of 38.9% (Hoy et al., 2012). Degenerative disc disease (DDD) is considered a major contributor to LBP (Luoma et al., 2000). Currently both surgical and non-surgical treatments for DDD induced LBP are able to alleviate symptoms but they don't provide a mechanism for preventing the progression of disc degeneration, thus, often LBP may return after treatment (Von Korff and Saunders, 1996). In order to effectively treat DDD induced LBP on a long-term basis, therapeutic methods that can slow DDD progression and reduce the need for surgical intervention are needed. Regarding DDD, its progression has been associated with the action of inflammatory cytokines in the intervertebral disc (IVD) that signal the breakdown of the extracellular matrix (ECM) through their respective receptors (Millward-Sadler et al., 2009; Studer et al., 2011; Purmessur et al., 2013). Therefore a potential method for effectively slowing DDD progression could be to inhibit the catabolic signaling of these inflammatory cytokines in the IVD.

Inhibition of catabolic signaling by inflammatory cytokines may be done by delivering mesenchymal stem cells (MSCs) that are known to have therapeutic immunomodulatory properties (Wang et al., 2014). Delivery of MSCs for treatment of DDD has shown efficacy both pre-clinically and clinically in decreasing pain and/or promoting IVD tissue regeneration (Orozco et al., 2011; Marfia et al., 2014; Pettine et al., 2016; Chun et al., 2012). These therapeutic cells are believed to provide regenerative effects mostly by stimulating anabolic gene expression through paracrine signaling (Strassburg et al., 2010; Tam et al., 2014). This is useful in providing a short term regenerative effect but the long term effects of this mechanism of action are unclear. In some aspects, in order to provide long term effects delivered MSCs must remain viable in the IVD. This likely requires them to differentiate into nucleus pulposus (NP) or chondrocyte like cells in order to withstand the low pH, high osmolarity environment of the IVD (Wuertz et al., 2008; Liang et al., 2012). With increased levels of inflammatory cytokines TNF-α and IL-1β known to be in the degenerative IVD (Le Maitre et al., 2007; Weiler et al., 2005) differentiation may be inhibited (Wehling et al., 2009; Heldens et al., 2012). Therefore to promote survival and regeneration by implanted MSCs in the IVD, it may be beneficial to regulate signaling of TNF-α and IL-1β in MSCs to be delivered to the degenerative IVD.

To regulate signaling of TNF-α and IL-1β, binding to their respective receptors must be inhibited. This may be achieved through cytokine specific inhibitors delivered directly or by gene therapy, but use of inhibitors has drawbacks. Regarding direct delivery, continuous delivery is needed for long-term inhibition due to the short half-life of the inhibitor molecules. Regarding both types of delivery, the inhibitors aren't cell or receptor specific, thus, they may inhibit any pathway that TNF-α and IL-1β signals, on any cell presenting the appropriate receptors within their vicinity. A more controllable method for inhibition of signaling is regulating the presence of the particular receptors as signal transducing receptors act upon the cells they are presented on and regulate specific pathways. Being able to regulate specific pathways is important as not all functions of these inflammatory cytokines are negative. For example, concerning TNF-α receptor signaling through TNFR1 can result in either apoptotic or anti-apoptotic signaling but signaling through TNFR2 is known to result in anti-apoptotic pathways, thus, it is of interest to specifically target TNFR1 signaling (Cabal-Hierro and Lazo, 2012).

To decrease the presence of specific inflammatory cytokine receptors, one must regulate their protein or gene expression for which there are several methods available. A recently developed method of gene regulation at the genomic level, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) based epigenome editing (Thakore et al., 2015; Larson et al., 2013), is of interest for regulating receptor expression and therefore signaling of inflammatory cytokines. It has been shown to perform highly specific and effective gene modulation in mammalian cells and has been shown to be more robust in downregulating expression compared to RNAi (Gilbert et al., 2014). A study described herein aimed to investigate the functional effects of regulating expression of TNFR1 and IL1R1, via CRISPR based epigenome editing. This was first screened in HEK293T cells to allow for rapid design, and then more thoroughly investigated in immortalized human adipose derived mesenchymal stem cells (hADMSCs). These hADMSCs were used as they provide an in vitro model for a clinically relevant cell population regarding cell delivery to the degenerative IVD. It was hypothesized that downregulation of TNFR1 and IL1R1 by epigenome editing will inhibit inflammatory signaling that results in ECM degradation, cell apoptosis, and inhibition of differentiation therefore engineering cells that are more likely to have a regenerative effect within the environment of the degenerative IVD once implanted.

The newly developed tool for endogenous gene regulation, CRISPR interference (CRISPRi), has the potential to provide effective multiplex gene regulation for applications in DDD. It has been shown that CRISPRi can perform specific and effective gene knockdown in mammalian cells in a single or multiplex manner [3]. As described herein, this system requires the expression of nuclease-inactive Cas9 (dCas9) by itself or fused to the Kruppel-associated box (KRAB) and the expression of short genomic loci-specific guide RNAs (gRNAs) that are complementary to the promoter of the gene [4]. As further disclosed herein, the CRISPRi system can be used to perform multiplex knockdown of inflammatory cytokine receptors and inhibit actions of inflammatory cytokines on cells in the IVD and retard the progression of DDD. Herein, the modulation of TNFR1 and IL1R1 using CRISPRi in both HEK293T cells and human nucleus pulpous cells and the ability to alter cell response to inflammatory challenge is demonstrated.

Described herein are compositions and methods directed to CRISPRi regulation of inflammation in the intervertebral disc and nervous system for the treatment of back pain related pathologies. The compositions described herein can be delivered directly to one or more intervertebral discs, for example, after a discectomy procedure to halt the progression of disc degeneration after surgery; delivered to adjacent intervertebral discs, for example, after spinal fusion surgery to halt the progression of disc degeneration (e.g., adjacent segment disease) after surgery; delivered to one or more peripheral nerves to, for example, antagonize sensitization of nociceptive neurons due to inflammatory signaling for the treatment of neuropathies, including but not limited to radiculopathy and discogenic back pain; and delivered to the central nervous system, for example, to antagonize altered neuronal signaling due to inflammatory signaling for the treatment of neuropathies, including but not limited to radiculopathy and discogenic back pain.

Compositions

The compositions disclosed herein include a CRISPR-Cas system. The CRISPR-Cas system can be non-naturally occurring. In some aspects, the CRISPR-Cas system comprises one or more vectors. In some aspects, the vectors can be singleplex or multiplex vectors. For example, vectors that can be used in the disclosed compositions and methods can include, but are not limited to the vectors shown in FIGS. 15-18. In an aspect, a singleplex vector is a repression vector. In an aspect, a singleplex vector is an upregulation vector. In an aspect, a multiplex vector is a repression vector. In an aspect, a multiplex vector is an upregulation vector. In an aspect, the vector is a combination repression, upregulation vector.

In some aspects, the one or more vectors comprise a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA). In some aspects, the gRNA can hybridize with a target sequence of a DNA molecule or locus in a cell. In some aspects, the one or more vectors can also comprise a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease. In some aspects, the promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA and the regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease can be located on the same or different vectors of the same system. The gRNA can target and hybridize with the target sequence. In some aspects, the gRNA can also direct the RNA-directed nuclease into the DNA molecule or locus. In some aspects, gRNA can be selected from the group listed in Tables 2 and 4.

As used herein, the term “regulatory element” refers to promoters, promoter enhancers, internal ribosomal entry sites (IRES) and other elements that are capable of controlling expression (e.g., transcription termination signals, including but not limited to polyadenylation signals and poly-U sequences). Regulatory elements can direct constitutive expression. Regulatory elements can be tissue-specific. Examples of tissue-specific promoters can direct expression in a desired tissue of interest (e.g., muscle, neuron, bone, skin, blood, intervertebral disc), specific organs (e.g., liver, pancreas, brain, spinal cord), or particular cell types (peripheral nerves, annulus fibrosus, nucleus pulposus, chondrocytes). Regulatory elements can also direct expression in a temporal-dependent manner including but not limited to cell-cycle dependent or developmental stage-dependent. Temporal-dependent expression can be tissue or cell-type specific. Regulatory element can also refer to enhancer elements. Examples of enhancer elements include but are not limited to WPRE, CMV enhancers, and SV40 enhancers. In an aspect, the regulatory element is hUbC. In an aspect, the hUbC promoter is operably linked to a nucleotide sequence encoding a RNA-directed nuclease. Generally, any constitutive promoter can be operably linked to a nucleotide sequence encoding a RNA-directed nuclease. Specific gene specific promoters can be used. Such promoters allow cell specific expression or expression tied to specific pathways. Any promoter that is active in mammalian cells can be used. In an aspect, the promoter is an inducible promoter including, but not limited to, Tet-on and Tet-off systems. Such inducible promoters can be used to control the timing of the desired expression.

The transcriptional control element can be a promoter. In an aspect, the promoter can be a mammalian cell active promoter (e.g., SV40, CMV, SP6, T7); a yeast active promoter (e.g., GAL4); a bacteria active promoter (e.g., Lac); or a baculovirus/insect cell active promoter (e.g., polyhedron). In an aspect, the transcriptional control element can be an inducible promoter. Examples of inducible promoters include but are not limited to tetracycline inducible system (tet); heat shock promoters and IPTG activated promoters.

Disclosed herein, are vectors comprising a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA and a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease. In some aspects, the gRNA sequence can be selected from the group listed in Table 2 and Table 4. In some aspects, the promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA and a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease can be on the same or different vectors of the same system.

Vectors include, but are not limited to nucleic acid molecules that are single-stranded double-stranded, or partially double-stranded; nucleic acid molecules that comprise one or more free ends, no free ends (e.g. circular); nucleic acid molecules that comprise DNA, RNA, or both; and other varieties of polynucleotides known in the art. One type of vector is a viral vector, wherein virally-derived DNA or RNA sequences are present in the vector for packaging into a virus. Viral vectors can include polynucleotides carried by a virus for transfection into a host cell. In some aspects, the CRISPR-Cas system described herein is packaged into a single lentiviral, adenoviral or adeno-associated virus particle.

The vectors disclosed herein can also include detectable labels. Such detectable labels can include a tag sequence designed for detection (e.g., purification or localization) of an expressed polypeptide. Tag sequences include, for example, green fluorescent protein, glutathione S-transferase, polyhistidine, c-myc, hemagglutinin, or Flag™ tag, and can be fused with the encoded nucleic acid.

Some vectors are capable of autonomous replication in a host cell which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) are integrated into the genome of a host cell upon introduction into the host cell, and are thereby replicated along with the host genome.

The term “expression vector” is herein to refer to vectors that are capable of directing the expression of genes to which they are operatively-linked. Common expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. Recombinant expression vectors can comprise a nucleic acid as disclosed herein in a form suitable for expression of the acid in a host cell. In other words, the recombinant expression vectors can include one or more regulatory elements or promoters, which can be selected based on the host cells used for expression that is operatively linked to the nucleic acid sequence to be expressed.

The term “operatively linked to” refers to the functional relationship of a nucleic acid with another nucleic acid sequence. Promoters, enhancers, transcriptional and translational stop sites, regulatory elements, regulatory control elements and other signal sequences are examples of nucleic acid sequences operatively linked to other sequences. For example, operative linkage of DNA to a transcriptional control element refers to the physical and functional relationship between the DNA and promoter such that the transcription of such DNA is initiated from the promoter by an RNA polymerase that specifically recognizes, binds to and transcribes the DNA.

One or more vectors can be introduced into a cell (e.g., a host cell) to produce transcripts, proteins, peptides including fusion proteins and peptides, encoded by nucleic acids as described herein (e.g., clustered regularly interspersed short palindromic repeats (CRISPR) transcripts, proteins, enzymes, mutant forms thereof, fusion proteins thereof, etc.). In some aspects, the vector is a viral vector. Examples of vectors include, but are not limited to lentiviruses, adenoviral, and adeno-associated viruses. The type of vector can also be selected for targeting a specific cell type.

The vectors disclosed herein can comprise one or more promoters or regulatory elements or the like. In an aspect, a vector comprises one or more pol promoters, one or more pol promoters II, one or more poll III promoters, or combinations thereof. Examples of pol II promoters include, but are not limited to the retroviral Rous sarcoma virus (RSV) LTR promoter (optionally with the RSV enhancer), the cytomegalovirus (CMV) promoter (optionally with the CMV enhancer), the SV40 promoter, the dihydrofolate reductase promoter, the β-actin promoter, the phospho glycerol kinase (PGK) promoter, and the EF1α promoter. In some aspects, pol II promoters can be engineered to confer tissue specific and inducible regulation of gRNAs. Examples of pol III promoters include, but are not limited to, U6 and H1 promoters. In an aspect, the promoter is U6. In an aspect, the promoter operably linked to the gRNA is a Pol III promoter, human u6, mouse U6, H1, or 7SK.

In some aspects, the compositions described herein (e.g., CRISPR-Cas systems, vectors) can comprise one or more promoters or regulatory elements. In the instance of two or more promoters or regulatory elements, said promoters or regulatory elements can be referred to as a first promoter, a second promoter and so on.

The vector or vector systems disclosed herein can comprise one or more vectors. Vectors can be designed for expression of CRISPR transcripts (e.g., nucleic acid transcripts, proteins, or enzymes) in prokaryotic or eukaryotic cells. CRISPR transcripts, for example, can be expressed in bacterial cells (e.g., Escherichia coli), insect cells (using baculovirus expression vectors), yeast cells, or mammalian cells. Alternatively, the recombinant expression vector can be transcribed and translated in vitro, for example, using T7 promoter regulatory sequences and T7 polymerase.

Generating constructs for the CRISPR/Cas9 system described herein can be a singleplex or multiplexed. The targets of the CRISPR/Cas9 system described herein can be multiplexed. In some aspects, the vectors can be singleplex vector or multiplex vectors. In some aspects, the singleplex or multiplex vectors can be repression or downregulation vectors or upregulation vectors or a combination thereof.

Vectors can be introduced in a prokaryote, amplified and then the amplified vector can be introduced into a eukaryotic cell. The vector can also be introduced in a prokaryote, amplified and serve as an intermediate vector to produce a vector that can be introduced into a eukaryotic cell (e.g., amplifying a plasmid as part of a viral vector packaging system). A prokaryote can be used to amplify copies of a vector and express one or more nucleic acids to provide a source of one or more proteins for delivery to a host cell or host organism. Expression of proteins in prokaryotes is often carried out in Escherichia coli with vectors containing constitutive or inducible promoters directing the expression of either fusion or non-fusion proteins. Vectors can also be a yeast expression vector (e.g., Saccharomyces cerivisaie).

In some aspects, the vector is capable of driving expression of one or more sequences in mammalian cells using a mammalian expression vector. Examples of mammalian expression vectors include but are not limited to pCDM8 and pMT2PC. In mammalian cells, regulatory elements control the expression of the vector. Examples of promoters are those derived from polyoma, adenovirus 2, cytomegalovirus, simian virus 40, and others disclosed herein and known in the art.

In some aspects, the regulatory element is operably linked to one or more elements of a CRISPR system to drive expression of the one or more elements of the CRISPR system. CRISPRs are a family of DNA loci that are generally specific to a particular species (e.g., bacterial species). The CRISPR locus comprises a distinct class of interspersed short sequence repeats (SSRs) that were identified in E. coli, and associated genes. The repeats can be short and occur in clusters that are regularly spaced by unique intervening sequences with a constant length.

As used herein, “CRISPR system” and “CRISPR-Cas system” refers to transcripts and other elements involved in the expression of or directing the activity of CRISPR-associated (“Cas”) genes, including sequences encoding a Cas gene, a guide sequence (also referred to as a “spacer” in the context of an endogenous CRISPR system; e.g. guide RNA or gRNA), or other sequences and transcripts from a CRISPR locus. In some aspects, one or more elements of a CRISPR system is derived from a type I, type II, or type III CRISPR system. In some aspects, one or more elements of a CRISPR system are derived from a particular organism comprising an endogenous CRISPR system, such as Streptococcus pyogenes. Generally, a CRISPR system is characterized by elements that promote the formation of a CRISPR complex at the site of a target sequence (also referred to as a proto spacer in the context of an endogenous CRISPR system).

As used herein, the term “target sequence” refers to a sequence to which a guide sequence (e.g. gRNA) is designed to have complementarity, where hybridization between a target sequence and a guide sequence promotes the formation of a CRISPR complex. Full complementarity is not necessarily required, provided there is sufficient complementarity to cause hybridization and promote formation of a CRISPR complex. A target sequence can comprise any polynucleotide, such as DNA or RNA polynucleotides. In some aspects, a target sequence is located in the nucleus or cytoplasm of a cell. In some aspects, the target sequence can be within an organelle of a eukaryotic cell (e.g., mitochondrion). A sequence or template that can be used for recombination into the targeted locus comprising the target sequences is referred to as an “editing template” or “editing polynucleotide” or “editing sequence.” Disclosed herein are target sequences. In an aspect, the target sequence(s) can be is selected from one or more of the sequences listed in Table 1 and 3.

A guide sequence (e.g. gRNA) can be any polynucleotide sequence having sufficient complementarity with a target polynucleotide sequence to hybridize with the target sequence and direct sequence-specific binding of a CRISPR-Cas system or CRISPR complex to the target sequence. In some aspects, the degree of complementarity between a guide sequence (e.g. gRNA) and its corresponding target sequence is about or more than about 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or more. In some aspects, a guide sequence is about more than about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 or more nucleotides in length or any number in between.

The target polynucleotide of a CRISPR complex can be any polynucleotide endogenous or exogenous to the eukaryotic cell. For example, the target polynucleotide can be a polynucleotide residing in the nucleus of the eukaryotic cell. The target polynucleotide can be a sequence coding a gene product (e.g., a protein) or a non-coding sequence (e.g., a regulatory polynucleotide or a junk DNA). It is believed that the target sequence should be associated with a PAM (protospacer adjacent motif); that is, a short sequence recognized the CRISPR complex. The precise sequence and length requirements for the PAM differ depending on the CRISPR enzyme used, but PAMs are typically 2-5 base pair sequences adjacent the protospacer (that is, the target sequence). A skilled person will be able to identify further PAM sequences for use with a given CRISPR enzyme. In an aspect, the PAM comprises NGG (where N is any nucleotide, (G)uanine, (G)uanine). The target sequence corresponds to one or more receptors. In an aspect, the target sequence is a tumor necrosis factor receptor (e.g., TNFR2), interleukin 1 receptor (e.g, IL1R2, IL6R), A-kinase anchor protein 5 (e.g., AKAP5), a glycoprotein (e.g., gp130) and transient receptor potential cation channel subfamily V member 1 (TRPV1). In an aspect, the target sequence can be selected from one or more of the sequences listed in Table 1 and Table 3.

Disclosed herein, are gRNA sequences. The disclosed gRNA sequences can be specific for one or more desired target sequences. In some aspects, the gRNA sequence hybridizes with a target sequence of a DNA molecule or locus in a cell. In an aspect, the gRNA sequence hybridizes to one or more target or targets sequences corresponding to including but not limited to dorsal root ganglion (e.g., peripherial cells), nocicipetive neurons (CGRP+(heat sensor); substance P; TRPV1, AKAP 79, AKAP 150 and nerve growth factor (NGF)). In some aspects, the cell can be a eukaryotic cell. In some aspects, the target sequences can be selected from one or more of the sequences listed in Table 1 and Table 3. In some aspects, the cell is a mammalian or human cell. In some aspects, the cell is a mesenchymal stem cell. In some aspects, the cell is an annulus fibrosus cell or nucleus pulposus cell. In some aspects, the cell can be any cell that can be delivered therapeutically to the disc, including but not limited to stem cells, or primary cells, such annulus fibrosus (AF) cells, nucleus pulposus (NP) cells, chondrocytes, fibroblasts. For direct gene therapy and delivery to the disc, the cell type can be any cell type in the IVD, including but not limited to AF and NP cells, as well as the chondrocytes in the endplate; and invading immune cells in the disc, including macrophages, T-cells, neutrophils. In an aspect, gRNA sequences target one or more cell type in the IVD.

In some aspects, the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA locus. In some aspects, the CRISPR-Cas system and vectors disclosed herein comprise one or more gRNA sequences. In some aspects, the gRNA sequences are listed in Tables 2 and 4. In some aspects, the target sequences can be selected from one or more of the sequences listed in Tables 1 and 3. In some aspects, the CRISPR-Cas system and vectors disclosed herein comprise 2, 3, 4 or more gRNA sequences. In some aspects, the CRISPR-Cas system and/or vector described herein comprises 4 gRNA sequences in a single system. In some aspects, the gRNA sequences disclosed herein can be used turn one or more genes on (p300core) or off (KRAB).

The compositions described herein can include a nucleic acid encoding a RNA-directed nuclease. The RNA-directed nuclease can be a CRISPR-associated endonuclease. In some aspects, the RNA-directed nuclease is a Cas9 nuclease or protein. In some aspects, the Cas9 nuclease or protein can have a sequence identical to the wild-type Streptococcus pyrogenes sequence. In some aspects, the Cas9 nuclease or protein can be a sequence for other species including, for example, other Streptococcus species, such as thermophilus; Psuedomona aeruginosa, Escherichia coli, or other sequenced bacteria genomes and archaea, or other prokaryotic microogranisms. In some aspects, the wild-type Streptococcus pyrogenes sequence can be modified. In some aspects, the nucleic acid sequence can be codon optimized for efficient expression in eukaryotic cells.

Disclosed herein, are CRISPR-Cas systems, referred to as CRISPRi (CRISPR interference), that utilizes a nuclease-dead version of Cas9 (dCas9). In some aspects, the dCas9 is used to repress expression of one or more target sequences (e.g., tumor necrosis factor receptor (e.g., TNFR2), interleukin 1 receptor (e.g, IL1R2, IL6R), A-kinase anchor protein 5 (e.g., AKAP5, a glycoprotein (e.g., gp130) and transient receptor potential cation channel subfamily V member 1 (TRPV1)). In some aspects, the target sequences can be selected from one or more of the sequences listed in Table 1 and Table 3. Instead of inducing cleavage, dCas9 remains bound tightly to the DNA sequence, and when targeted inside an actively transcribed gene, inhibition of, for example, pol II progression through a steric hindrance mechanism can lead to efficient transcriptional repression.

In some aspects, the CRISPR system can be used in which the nucleus has been deactivated. Further, a KRAB or p300 core can be attached. In some aspects, the KRAB is attached to downregulate one or more genes in a cell. In some aspects, the p300core is attached to upregulate one or more genes in a cell.

In some aspects, the CRISP-Cas system described herein can be used to upregulate or downregulate one or more genes in the same cell. In some aspects, the CRISP-Cas system described herein can also be used to upregulate and downregulate more than one gene or a combination thereof in the same cell. In an aspect, the expression of one or more genes (or gene products) can be decreased. In some aspects, the expression of one or more genes (or gene products) can be increased. In some aspects, the expression of one or more genes (or gene products) is increased and decreased.

In some aspects, the vector comprises a regulatory element operably linked to an enzyme-coding sequence encoding a CRISPR enzyme (e.g., a Cas protein). In some aspects, the CRISPR enzyme is Cas9 and can be from Streptococcus pyogenes, Streptococcus thermophiles, or Treponema centicola. In some aspects, the Cas9 is dCas9. In some aspects, the Cas9 protein can be codon optimized for expression in the cell.

In some aspects, dCas9 can be used to silence one or more target genes (e.g., TNFR2, IL1R2, IL6R, AKAP5, gp130 and TRPV1). For example, dCas9 can be used to silence one or more genes through steric hindrance with or without an attached domain, such as KRAB. dCas9 is the protein that interacts with gRNAs to place the desired editing proteins to specific sites. dCas9 can be used to silence (downregulate or turn off one or more genes). In some aspects, the dCas9 can be attached to KRAB to knockdown, silence or downregulate one or more genes. In some aspects, the dCas9 can be attached to p300 core to turn on or upregulate one or more genes. Other proteins can be further attached to dCas9 or included in the CRISPR-Cas system and/or vectors described herein. For example, T2A, a self-cleaving peptide, can be included. T2A allows selection markers (e.g., GFP, fluorescent proteins, antibiotics) to also be attached. The attachment of such markers can be included to permit detection or selection of cells expressing the CRISPR-Cas system and/or vectors described herein

Multiple gRNAs can be used to control multiple different genes simultaneously (multiplexing gene targeting), as well as to enhance the efficiency of regulating the same gene target.

TABLE 1 Examples of Target Sequences Target SEQ ID Gene Name Sequence NO. TNFR2 gRNA 1 5′-GAAGGCTGGATGCGTGTTTA-3′ 13 TNFR2 gRNA 2 5′-TCAAGTGATCTTCCCGCCTC-3′ 14 TNFR2 gRNA 3 5′-GTGAGGGTGAGGCACTAATT-3′ 15 TNFR2 gRNA 4 5′-CGGGCTTTCGCTTTCAGTCG-3′ 16 TNFR2 gRNA 5 5′-AGGTATCGGCCCAGCGATGC-3′ 17 TNFR2 gRNA 6 5′-CATGTCCTAAAATCACGAAC-3′ 18 TNFR2 gRNA 7 5′-AATTGTGATACTAGCGGTTA-3′ 19 IL1R2 gRNA 1 5′-AGGATAAAACTAGGGCCCAT-3′ 20 IL1R2 gRNA 2 5′-CAAGGTTTTACGCTCCCATT-3′ 21 IL1R2 gRNA 3 5′-GGGAGGTGACACCCAGTTTA-3′ 22 IL6R gRNA 1 5′-TAAACACCTGACACACGGTC-3′ 23 IL6R gRNA 2 5′-CGGAAGACTCACCACCGTAA-3′ 24 IL6R gRNA 3 5′-AGGGCGTATCAGCCACCAGT-3′ 25 IL6R gRNA 4 5′-CGGCTTTCGTAACCGCACCC-3′ 26 IL6R gRNA 5 5′-AGAGCCGGGCTCCTGCGGAT-3′ 27 gp130 gRNA 1 5′-AGGCTCGTTTACGTAAGTCT-3′ 28 gp130 gRNA 2 5′-GGAATAACGGGGTCATGAAC-3′ 29 gp130 gRNA 3 5′-CAGTGGCCGCCTGTCGACGA-3′ 30 gp130 gRNA 4 5′-CGCACGAACCCCTTGGCGCC-3′ 31 AKAP5 gRNA 1 5′-TCAACAGGATCACGACCTTA-3′ 32 AKAP5 gRNA 2 5′-ATCGTGGTTCATCGCCAAAC-3′ 33 AKAP5 gRNA 3 5′-GCTGCATCTCTATGCGGACA-3′ 34 AKAP5 gRNA 4 5′-TTAGCGTCTCAGAAAACGCG-3′ 35 AKAP5 gRNA 5 5′-AAACTGTGCATAGAATAGCG-3′ 36 AKAP5 gRNA 6 5′-AAGATCAACGTAGGGCGTCG-3′ 37 AKAP5 gRNA 7 5′-CCTTGCTCCGGGTGCGACCG-3′ 38 AKAP5 gRNA 8 5′-GCGCCCGGGCGGAGCACGAT-3′ 39 TRPV1 gRNA 1 5′-AATTAGCTGGGCGCAATGGC-3′ 40 TRPV1 gRNA 2 5′-GAGTAGGGGTTGGCGTCGAG-3′ 41 TRPV1 gRNA 3 5′-GACGCTAGTTTTGACGTCGC-3′ 42 TRPV1 gRNA 4 5′-GAGTCGCTGTGGACGCCCTT-3′ 43 TRPV1 gRNA 5 5′-TGAAGGCGGTTGCTACTCGA-3′ 44 TRPV1 gRNA 6 5′-AAGGCAGCTGCTTGCATCGC-3′ 45

TABLE 2 Examples of Guide RNA Sequences (gRNAs) Target SEQ ID Gene Name Sequence NO. TNFR2 gRNA 1 5′-GAAGGCUGGAUGCGUGUUUA-3′ 46 TNFR2 gRNA 2 5′-UCAAGUGAUCUUCCCGCCUC-3′ 47 TNFR2 gRNA 3 5′-GUGAGGGUGAGGCACUAAUU-3′ 48 TNFR2 gRNA 4 5′-CGGGCUUUCGCUUUCAGUCG-3′ 49 TNFR2 gRNA 5 5′-AGGUAUCGGCCCAGCGAUGC-3′ 50 TNFR2 gRNA 6 5′-CAUGUCCUAAAAUCACGAAC-3′ 51 TNFR2 gRNA 7 5′-AAUUGUGAUACUAGCGGUUA-3′ 52 IL1R2 gRNA 1 5′-AGGAUAAAACUAGGGCCCAU-3′ 53 IL1R2 gRNA 2 5′-CAAGGUUUUACGCUCCCAUU-3′ 54 IL1R2 gRNA 3 5′-GGGAGGUGACACCCAGUUUA-3′ 55 IL6R gRNA 1 5′-UAAACACCUGACACACGGUC-3′ 56 IL6R gRNA 2 5′-CGGAAGACUCACCACCGUAA-3′ 57 IL6R gRNA 3 5′-AGGGCGUAUCAGCCACCAGU-3′ 58 IL6R gRNA 4 5′-CGGCUUUCGUAACCGCACCC-3′ 59 IL6R gRNA 5 5′-AGAGCCGGGCUCCUGCGGAU-3′ 60 gp130 gRNA 1 5′-AGGCUCGUUUACGUAAGUCU-3′ 61 gp130 gRNA 2 5′-GGAAUAACGGGGUCAUGAAC-3′ 62 gp130 gRNA 3 5′-CAGUGGCCGCCUGUCGACGA-3′ 63 gp130 gRNA 4 5′-CGCACGAACCCCUUGGCGCC-3′ 64 AKAP5(79) gRNA 1 5′-UCAACAGGAUCACGACCUUA-3′ 65 AKAP5(79) gRNA 2 5′-AUCGUGGUUCAUCGCCAAAC-3′ 66 AKAP5(79) gRNA 3 5′-GCUGCAUCUCUAUGCGGACA-3′ 67 AKAP5(79) gRNA 4 5′-UUAGCGUCUCAGAAAACGCG-3′ 68 AKAP5(79) gRNA 5 5′-AAACUGUGCAUAGAAUAGCG-3′ 69 AKAP5(79) gRNA 6 5′-AAGAUCAACGUAGGGCGUCG-3′ 70 AKAP5(79) gRNA 7 5′-CCUUGCUCCGGGUGCGACCG-3′ 71 AKAP5(79) gRNA 8 5′-GCGCCCGGGCGGAGCACGAU-3′ 72 TRPV1 gRNA 1 5′-AAUUAGCUGGGCGCAAUGGC-3′ 73 TRPV1 gRNA 2 5′-GAGUAGGGGUUGGCGUCGAG-3′ 74 TRPV1 gRNA 3 5′-GACGCUAGUUUUGACGUCGC-3′ 75 TRPV1 gRNA 4 5′-GAGUCGCUGUGGACGCCCUU-3′ 76 TRPV1 gRNA 5 5′-UGAAGGCGGUUGCUACUCGA-3′ 77 TRPV1 gRNA 6 5′-AAGGCAGCUGCUUGCAUCGC-3′ 78

Methods

Methods of designing gRNAs. In some aspects, a commercially available tool, such as the UCSC genome browser (GRCh37/hg19), can be used to select sequences for the 5-UTR and the promoter region, 1000 base pairs upstream that can be entered into the CRISPR design tool (crispr.mit.edu). The design tool outputs 20 base pair gRNAs that are followed on their 3′ end by the PAM sequence NGG, which is specific to the CRISPR-Cas9 system derived from Streptococcus pyogenes. The design tool can also score the potential gRNA sequences based on the number of off-target sties they may have and how many are within genes. The score ranges from 0-100, with a higher score meaning less off-target sites within genes. Guide RNAs described herein, for example, that had a score of 75 and above were selected for further study. The selected gRNAs can then be entered into the BLAT tool of the UCSC genome browser to inspect for overlap of gRNAs with DNAse hypersensitivity sites to ensure overlap. Any site that has DNAse hypersensitivity value above 0.01 can be targeted with a guide if one is available from the list of guides generated as described above. Additionally, any site that shows greater than 10 transcription factor binding sites within a region, as determined from ChiP-seq, can also be considered. Generally, the DNAse hypersensitivity data is consistent with these regions. Using the criteria described above, gRNAs (e.g., 4-7 gRNAs) that are spaced at least 100 base pairs apart can be selected for performing targeted gene repression and screening. In an aspect, TNFR1, TNFR2, IL1R2, IL6R, IL1R1, AKAP5, gp130, and TRPV1 gRNAs guides can be screening using the method disclosed herein. In an aspect, gRNA sequences from the promoter region and 5′UTR (crispr.mit.edu) can be selected. In an aspect, gRNA sequences are 20 bp in length followed by a PAM sequence (e.g., NGG). In an aspect, gRNA sequences with the least off-target sequences and those that overlap with DNase sensitivity peaks can be selected.

Disclosed herein are methods of modulating expression of a gene in a cell. The method can include one or more of the following steps. First, introducing into a cell, a first nucleic acid. The first nucleic acid can encode a guide RNA comprising a DNA-binding domain. The nucleic acid can be operably linked to a regulatory element. The guide RNA described herein can be complementary to a target nucleic acid sequence disclosed herein comprising the gene. Next, a second nucleic acid encoding a transcriptional regulator protein or domain that modulates the target nucleic acid expression can be introduced into the cell. The second nucleic acid can further include a gRNA-binding domain. The second nucleic acid can be operably linked to a regulatory element. A third nucleic acid encoding a Cas9 (e.g., a deactivated nuclease (dCas9)) protein can be introduced. In an aspect, nuclease function can be removed. The third nucleic acid can be operably linked to a regulatory element. The Cas9 protein (e.g., dCas9) can interact with the guide RNA, and can be fused to the transcriptional regulator protein. The cell can then produce the guide RNA. The guide RNA can bind to the dCas9 protein and the transcriptional regulator protein or domain fused to the DNA-binding domain, and direct the complex (e.g., gRNA/dCas9 complex; the combined product of the gRNA and dCas9 interacting) to the DNA regulatory element encoded in the DNA-binding domain. The guide RNA and the dCas9 protein, for example, can co-localize to the target nucleic acid sequence. The transcriptional regulator protein or domain can modulate (increase or decrease) expression of the gene. The gRNA sequence can selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods for introducing into a cell a CRISPR-Cas system. In some aspects, the CRISPR-Cas system can include one or more vectors described herein. In some aspects, the method can include one or more vectors. For example, the vector can comprise a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA. In some aspects, the gRNA can hybridize with a target sequence of a DNA molecule in a cell. In some aspects, the vector can also include a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease. In some aspects, the promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA and the regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease can be located on the same or different vectors of the same system. In some aspects, the method also includes a step wherein the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA molecule. In some aspects, the gRNA sequence can be selected from the group listed in Table 2 and Table 4. In some aspects, the target sequence can be selected from one or more of the sequences listed in Table 3 and 4.

Disclosed herein, are methods for introducing into a cell a vector. In some aspects, the vector can include a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system gRNA. In some aspects, the vector can also include a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease. In some aspects, the gRNA sequence can be selected from the group listed in Table 2 and Table 4.

Disclosed herein, are methods for inducing site-specific DNA cleavage in a cell. The method can contacting a cell with a guide RNA. The guide RNA can be selected from the group listed in Table 2 and Table 2. The guide RNA can include a sequence capable of binding to a target DNA. The method can further comprise the following step: contacting the cell with a Cas9 protein. In an aspect, the DNA is in a cell. In an aspect, the cell is a eukaryotic cell. In an aspect, the cell is in an individual. In an aspect, the individual is a human.

The method steps described herein can be carried out simultaneously or sequentially in any order. In some aspects, the DNA can be in a cell. In some aspects, the cell can be a eukaryotic cell. In some aspects, the cell can be in an individual. In some aspects, the individual can be a human.

Method of Treatment

The methods disclosed herein can be useful for the treatment of a subject having lower back pain. The methods disclosed herein can be effective for targeting one or more receptors, including tumor necrosis factor receptor (e.g., TNFR2, TNFR1), interleukin 1 receptor (e.g, IL1R2, IL1R1, IL6R), A-kinase anchor protein 5 (e.g., AKAP5), a glycoprotein (e.g., gp130) and transient receptor potential cation channel subfamily V member 1 (TRPV1). In some aspects, the method scan also include the step of administering a therapeutic effective amount of the compositions disclosed herein (e.g., a CRISPR-Cas system comprising one or more vectors comprising: a) a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA), wherein the gRNA hybridizes with a target sequence of a DNA locus in a cell; and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein components a) and b) are located on the same or different vectors of the same system, wherein the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA locus; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4. In some aspects, the target sequences can be selected from one or more of the sequences listed in Table 1 and Table 3. In some aspects, the methods can further include the step of identifying a subject (e.g., a human patient) who has low back pain and then providing to the subject a composition comprising the CRISPR-Cas system or vector disclosed herein. In some aspects, the back pain can be caused by degenerative disc disease, dicogenic, one or more facet joints, one or more muscles, inflammation or changes inflammatory cytokines. In some aspects, the subject can be identified using standard clinical tests known to those skilled in the art. Examples of tests for diagnosing degenerative disc disease include imaging (e.g., MRI, T2 weighted, T1rho). Subjects can also be identified as having axial back pain through self-reporting and completing the Oswestry low back disability questionnaire.

The therapeutically effective amount can be the amount of the composition administered to a subject that leads to a full resolution of the symptoms of the condition, disease or pain, a reduction in the severity of the symptoms of the condition, disease or pain, or a slowing of the progression of symptoms of the condition, disease or pain. The methods described herein can also include a monitoring step to optimize dosing. The methods can also include the step of determining the nucleic acid sequence of the specific cytokine or receptor present in a subject's DNA and then design the CRISPR-Cas system or vectors to comprise specific DNA binding domain sequences or gRNA sequences. The compositions described herein can be administered as a preventive treatment or to delay or slow the progression of degenerative changes or at the time of surgery.

The compositions disclosed herein can be used in a variety of ways. For instance, the compositions disclosed herein can be used for direct delivery of modified therapeutic cells, or lentivirus. The compositions disclosed herein can be used or delivered or administered at any time during the treatment process (e.g., during an already conducted surgery, when either a spinal fusion is being conducted, or a microdiscectomy). The compositions described herein including cells or a virus can be delivered to the affected level in the microdiscetomy case, or to the adjacent levels to stop adjacent segment disease in the spinal fusion case.

In some aspects, the compositions disclosed herein can be administered or delivered to peripheral neurons (e.g., to regulate inflammatory interactions with the pain sensing neurons). Such treatment can be carried out if this type of interaction is suspected in back pain.

The dosage to be administered depends on many factors including, for example, the route of administration, the formulation, the severity of the patient's condition/disease/pain, previous treatments, the patient's size, weight, surface area, age, and gender, other drugs being administered, and the overall general health of the patient including the presence or absence of other diseases, disorders or illnesses. Dosage levels can be adjusted using standard empirical methods for optimization known by one skilled in the art. Administrations of the compositions described herein can be single or multiple (e.g., 2- or 3-, 4-, 6-, 8-, 10-, 20-, 50-, 100-, 150-, or more fold). Further, encapsulation of the compositions in a suitable delivery vehicle (e.g., polymeric microparticles or implantable devices) can improve the efficiency of delivery.

The therapeutically effective amount of the compositions described herein can include a single treatment or a series of treatments (i.e., multiple treatments or administered multiple times). Treatment duration using any of compositions disclosed herein can be any length of time, such as, for example, one day to as long as the life span of the subject (e.g., many years). For instance, the composition can be administered daily, weekly, monthly, yearly for a period of 5 years, ten years, or longer. The frequency of treatment can vary. For example, the compositions described herein can be administered once (or twice, three times, etc.) daily, weekly, monthly, or yearly for a 15 period of 5 years, ten years, or longer.

In some aspects, the compositions disclosed herein can also be co-administered with another therapeutic agent or in combination with microdiscectomy or spinal fusion surgery.

In some aspects, the methods disclosed herein also include treating a subject having degenerative disc disease. In some aspects, the methods disclosed herein can include the step of determining TNF, IL1, IL6, IL8, IFN-gamma and/or IL17 levels in a subject. In some aspects, the disclosed methods can further include the step of administering to the subject a pharmaceutical composition comprising a nucleic acid sequence encoding a CRISPR-associated endonuclease (e.g., deactivated endonuclease) and one or more guide RNAs, wherein the guide RNA is selected from the group listed in Table 2 and Table 4. In some aspects, the CRISPR-associated endonuclease is optimized for expression in a human cell.

Pharmaceutical Compositions

As disclosed herein, are pharmaceutical compositions, comprising the compositions disclosed herein. For example, disclosed are pharmaceutical compositions, comprising a vector or CRISPR-Cas system comprising one or more vectors comprising: a) a promoter operably linked to one or more nucleotide sequences encoding a CRISPR-Cas system guide RNA (gRNA), wherein the gRNA hybridizes with a target sequence of a DNA locus in a cell; and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein components a) and b) are located on the same or different vectors of the same system, wherein the gRNA targets and hybridizes with the target sequence and directs the RNA-directed nuclease to the DNA locus; wherein the gRNA sequence is selected from the group listed in Table 2 and Table 4. In some aspects, the target sequence can be selected from one or more of the sequences listed in Table 1 and Table 3. In some aspects, the pharmaceutical compositions comprise the any one of the CRISPR-Cas system disclosed herein. In some aspects, the pharmaceutical composition comprises the nucleic acid sequence of any of the vectors or CRISPR-Cas systems disclosed herein. In some aspects, the pharmaceutical compositions further comprise a pharmaceutically acceptable carrier.

As used herein, the term “pharmaceutically acceptable carrier” refers to solvents, dispersion media, coatings, antibacterial, isotonic and absorption delaying agents, buffers, excipients, binders, lubricants, gels, surfactants that can be used as media for a pharmaceutically acceptable substance. The pharmaceutically acceptable carriers can be lipid-based or a polymer-based colloid. Examples of colloids include liposomes, hydrogels, microparticles, nanoparticles and micelles. The compositions can be formulated for administration by any of a variety of routes of administration, and can include one or more physiologically acceptable excipients, which can vary depending on the route of administration. Any of the nucleic acids and vectors and gRNAs described herein can be administered in the form of a pharmaceutical composition.

As used herein, the term “excipient” means any compound or substance, including those that can also be referred to as “carriers” or “diluents.” Preparing pharmaceutical and physiologically acceptable compositions is considered routine in the art, and thus, one of ordinary skill in the art can consult numerous authorities for guidance if needed. The compositions can also include additional agents (e.g., preservatives).

The pharmaceutical compositions as disclosed herein can be prepared for oral or parenteral administration. Pharmaceutical compositions prepared for parenteral administration include those prepared for intravenous (or intra-arterial), intramuscular, intervertebral subcutaneous, facet joint, dorsal root ganglion, intrathecal or intraperitoneal administration. Paternal administration can be in the form of a single bolus dose, or may be, for example, by a continuous pump. In some aspects, the compositions can be prepared for parenteral administration that includes dissolving or suspending the CRISPR-Cas systems, nucleic acids, polypeptide sequences or vectors in an acceptable carrier, including but not limited to an aqueous carrier, such as water, buffered water, saline, buffered saline (e.g., PBS), and the like. One or more of the excipients included can help approximate physiological conditions, such as pH adjusting and buffering agents, tonicity adjusting agents, wetting agents, detergents, and the like. Where the compositions include a solid component (as they may for oral administration), one or more of the excipients can act as a binder or filler (e.g., for the formulation of a tablet, a capsule, and the like). Where the compositions are formulated for application to the skin or to a mucosal surface, one or more of the excipients can be a solvent or emulsifier for the formulation of a cream, an ointment, and the like.

In some aspects, the CRISPR-Cas system disclosed herein can be directly injected via a lentivirus into the IVD without a carrier or with a biomaterial carrier. Any hydrogel or biomaterial designed for viral vector delivery can be used.

In some aspects, the cells can be administered to a desired location with or without a biomaterial carrier.

In some aspects, a virus comprising one or more vectors disclosed herein or the CRISPR-Cas system disclosed herein can be administered with or without a carrier to one or more peripheral nerves. In some aspects, the one or more peripheral nerves can be innervating the disc. Thus, the administration of the virus comprising any one of the compositions disclosed herein can be delivered (e.g., injected) to the disc site or dorsal root ganglion (DRG).

In some aspects, the compositions disclosed herein are formulated for intervertebral administration

The pharmaceutical compositions can be sterile and sterilized by conventional sterilization techniques or sterile filtered. Aqueous solutions can be packaged for use as is, or lyophilized, the lyophilized preparation, which is encompassed by the present disclosure, can be combined with a sterile aqueous carrier prior to administration. The pH of the pharmaceutical compositions typically will be between 3 and 11 (e.g., between about 5 and 9) or between 6 and 8 (e.g., between about 7 and 8). The resulting compositions in solid form can be packaged in multiple single dose units, each containing a fixed amount of the above-mentioned agent or agents, such as in a sealed package of tablets or capsules. The composition in solid form can also be packaged in a container for a flexible quantity, such as in a squeezable tube designed for a topically applicable cream or ointment. The compositions can also be formulated as powders, elixirs, suspensions, emulsions, solutions, syrups, aerosols, lotions, creams, ointments, gels, suppositories, sterile injectable solutions and sterile packaged powders. The active ingredient can be nucleic acids or vectors described herein in combination with one or more pharmaceutically acceptable carriers. As used herein “pharmaceutically acceptable” means molecules and compositions that do not produce or lead to an untoward reaction (i.e., adverse, negative or allergic reaction) when administered to a subject as intended (i.e., as appropriate).

In some aspects, the CRISPR-Cas system, vectors, gRNAs and nucleic acid sequences as disclosed herein can be delivered to a cell of the subject. In some aspects, such action can be achieved, for example, by using polymeric, biodegradable microparticle or microcapsule delivery vehicle, sized to optimize phagocytosis by phagocytic cells (e.g., macrophages).

In some aspects, the formulations include any that are suitable for the delivery of a virus (e.g., lentivirus) and cells. In an aspect, the route of administration includes but is not limited to injection into the disc, adjacent to the disc, or directly to the DRG for peripheral neuron transduction. Such administration can be done without surgery, or with surgery.

Kits

The kits described herein can include any combination of the compositions (e.g., CRISR-Cas system or vectors) described above and suitable instructions (e.g., written and/or provided as audio-, visual-, or audiovisual material). In an aspect, the kit comprises a predetermined amount of a composition comprising any one of the CRISPR-Cas or vectors disclosed herein. The kit can further comprise one or more of the following: instructions, sterile fluid, syringes, a sterile container, delivery devices, and buffers or other control reagents.

EXAMPLES Example 1: CRISPR Epigenomic Editing of AKAP 150 in DRG Neurons Abolished Degenerative IVD Induced Sensitization of Sensory Neurons

Materials and Methods

Experimental Overview.

A set of four experiments was conducted in the degenerative IVD environment (e.g., inflammatory cytokines and low pH) on the sensitization of DRG neurons to noxious stimuli and to elucidate the factors and mechanisms mediating this sensitization. In the Degenerative IVD Conditioned Media Exposure experiments, rat DRG neurons were subjected to a range of temperatures during human degenerative and healthy IVD conditioned media exposure to determine the ability of factors released from degenerative IVD tissue to sensitize neurons and the magnitude of that sensitization. Following the degenerative IVD conditioned media exposure experiment, the IL-6 Blocking Experiments were performed to determine the role of IL-6 in the degenerative IVD sensitization of peripheral neurons. Once IL-6 was implicated as a mediator of neuron sensitization, the AKAP Inhibition Experiments were conducted to determine the mechanism by which IL-6 sensitizes DRG neurons. Following TRPV1 involvement in DRG sensitization, the Acidic pH-Degenerative IVD Conditioned Media Exposure experiments were conducted to determine the role of pH in DRG neuron sensitization and its ability to interact with the observed inflammation driven sensitization.

Once the IL-6/AKAP/TRPV1 pathway was identified as the main pathway for degenerative IVD induced neuron sensitization, the potential of CRISPR epigenome editing of neurons to regulate degenerative IVD induced sensitization via the targeting of AKAP in this pathway was investigated. Lentiviral constructs carrying the CRISPR epigenome editing system that targeted the AKAP gene promoter were designed, built, and validated for their ability to regulate AKAP expression in peripheral neurons. Validated CRISPR AKAP targeting epigenome editing vectors were selected, and delivered to DRG neurons prior to exposure to degenerative IVD sensitization model and tested for an ability to regulate previously demonstrated sensitization via IL-6/AKAP/TRPV1 pathway.

Degenerative Intervertebral Disc (IVD) Conditioned Media.

IVD tissue was obtained from five patients undergoing surgical intervention for axial back pain, degenerative disc disease, and lumbar spondylosis. IVD tissue was extracted from lumbar discs for all patients. Patients showed signs of degenerative disc disease on magnetic resonance imaging (MRI) and reported axial back pain. Additionally, non-degenerative IVD tissue was obtained from three trauma patients with no prior history of axial back or neck pain. IVD tissue was transferred into a glass petri dish, washed twice in washing medium (DMEM-HG (Life Technologies) supplemented with 1% gentamycin (Gibco), 1% kanamycin (Sigma) and 1% fungizone (Gibco)) and cut into small pieces (˜3 mm²). Next, the IVD tissue was weighed, transferred to a 75 cm² tissue culture flask, and cultured in DMEM-HG supplemented with 50 μg/ml ascorbic acid (Life Technologies), 5 μg/ml gentamicin, and 0.125 μg/ml fungizone at a media to tissue ratio of 3.5 ml/g for 48 hours (37° C. and 5% CO₂)[33]. After incubation, IVD conditioned media was collected, and stored at −80° C. until needed.

Dorsal Root Ganglion (DRG) Neuron Cell Culture.

Postnatal (p1-p4) Sprague Dawley rat DRGs were explanted, placed in L-15 medium (Gibco), and cleaned of anterior and posterior roots and connective tissue. Ganglia were dissociated in 2 mL of L-15 medium supplemented with 500 μL of collagenase IV (1.33%, Worthington Biochemical) for 30 minutes at 37° C. The cell suspension was centrifuged at 1000 RPM for 5 minutes after which the supernatant was aspirated and the cells were incubated in 4 mL of DMEM/F-12 supplemented with 1 mL of 1% trypsin (Worthington Biochemical) plus 504 of 1% DNase I (Worthington Biochemical) for 20 minutes at 37° C. Following incubation, 1 mL of soybean trypsin inhibitor (SBTI) (Worthington Biochemical) was added to the cell suspension and the cell suspension was centrifuged at 1000 RPM for 5 minutes. Next, the supernatant was aspirated, cells were resuspended in 1 mL of DMEM/F-12 plus 50 μL of 1% DNase and triturated through a fire polished Pasteur pipette. Rat DRG neurons were seeded onto laminin (Life Technologies) coated 35 mm tissue culture dishes at a density of 50,000 cells per dish and cultured in 1.5 mL of SATO⁻ medium (DMEM/F12 supplemented with 2.2% SATO-mix, 1% transferrin (Sigma), 2% insulin (Sigma), 1% Glutamax (Invitrogen), 0.5% gentamicin, and 2.5 S NGF (long/ml, Worthington Biochemical) for 2-6 days until experiment.

Calcium Imaging of Action Potentials.

Rat DRG neurons were loaded with the calcium indicator dye Fluo-4AM (Molecular Probes, 304) and incubated in the dark at 37° C. for 1 hour. Fluorescent measurements of calcium were performed using a multi-photon microscope (Bruker/Prairie View, excitation 810 nm, emission 545 nm, 0.5 Hz). Neurons were incubated at 37° C. for 15 minutes to establish the baseline calcium signal and then exposed to heat stimuli for two minutes while imaging. Cells were returned to the baseline temperature for 5 minutes between exposures to elevated temperatures. 100 DRG neurons were imaged and analyzed for each treatment group.

Image analysis was conducted using Fiji software[50]. The background signal was subtracted from each cell and the mean baseline (F₀(t)) was calculated at 37° C.

$\begin{matrix} {\frac{\Delta\; F}{F} = \frac{\left( {{F(t)} - {F_{0}(t)}} \right)}{F_{0}(t)}} & \lbrack 1\rbrack \end{matrix}$

was calculated for each cell across the entire experiment. The baseline mean and standard deviation of ΔF/F was calculated for all cells at 37° C. Neurons were considered to be firing (generating an action potential) in response to heat stimuli if the ΔF/F for the cell was 3 standard deviations greater than the mean baseline value[19] at 37° C. (FIG. 1) in response to heat stimulation.

Degenerative IVD Conditioned Media Exposure.

Media were replaced with fresh SATO-media and 0.75 ml of unconditioned DMEM (control media, n=5), degenerative IVD conditioned (n=5 patients), or healthy IVD conditioned media (n=3 patients) and cultured for 24 hours (37° C., 5% CO₂). Following incubation, neurons were loaded with the calcium indicating dye Fluo-4AM as described in the Calcium Imaging of Action Potentials section. Neurons were incubated at 37° C. for 15 minutes to establish a baseline calcium signal and then exposed to heat of 38, 39, 40, 42, and 44° C. for two minutes while imaging. Cells were returned to the baseline temperature for 5 minutes between exposures to elevated temperatures.

IL-6 Blocking Experiments.

Mouse monoclonal anti-human IL-6 antibody (Life Technologies, 20 μg/mL) or mouse isotype control antibody (Life Technologies, 20 μg/mL) were added to degenerative IVD conditioned media and incubated at 37° C. for three hours prior to addition to neurons as described in the Degenerative IVD Conditioned Media Exposure section (n=5 patients). Degenerative IVD conditioned media not receiving antibody treatment and control media (DMEM supplemented with 5 μg/ml gentamicin and 0.125 μg/ml fungizone) were incubated at 37° C. for three hours prior to addition to neurons as described in the Degenerative IVD Conditioned Media Exposure section (n=5). Neurons were incubated at 37° C. for 15 minutes to establish a baseline calcium signal and then exposed to heat stimulation of 38, 39, 40, 42, and 44° C. for two minutes while imaging. Cells were returned to the baseline temperature for 5 minutes between exposures to elevated temperatures.

AKAP Inhibition Experiments.

DRG neurons were loaded with the calcium dye Fluo-4AM (3 μM) and incubated in the dark at 37° C. for 1 hour. The AKAP inhibitor peptide St-Ht31 (Promega, 50 μM) or the control peptide St-Ht31P (Promega, 50 μM) were added to the DRG neurons and incubated at 37° C. for 15 minutes. Following incubation, degenerative IVD conditioned media (n=3 patients) or control media were added to the peptide exposed neurons and incubated for 15 minutes (n=3). Additionally, separate groups of neurons were exposed to control media or degenerative IVD conditioned media without peptide exposure under the same conditions (n=3 patients). Following this incubation, a 15 minute baseline calcium signal at 37° C. was established and cells were exposed to heat stimulation of 39° C. while imaging.

Acidic pH-Degenerative IVD Conditioned Media Exposure.

Experiments were conducted as described in the Degenerative IVD Conditioned Media Exposure section (n=4 patients) with the following experimental treatment groups: normal pH (7.4) control media (DMEM), normal pH (7.4) IVD conditioned media, low pH (6.5) control media, and low pH (6.5) IVD conditioned media. Control media (DMEM) or degenerative IVD conditioned media were equilibrated in an incubator for 24 hours (37° C., 5% CO₂). Following incubation, the pH of the acidic pH groups was lowered to a pH of 6.5 by the addition of HCL (1M, Sigma-Aldrich) and the normal pH groups maintained at a pH of 7.4.

Lentiviral CRISPR Epigenome Editing Vector Construction.

CRISPR epigenome editing vectors were created that co-expresses dCAS-KRAB-T2A-GFP and gRNAs that target AKAP 150. First, the promoter region of rat AKAP 150 are screened for gRNA target sequences with the necessary adjacent protospacer adjacent motif (PAM: −NGG) and selected based on minimizing off-target binding sites using a publically available algorithm[21]. Four guides are screened per promoter region that target every ˜250 bp (data and sequences obtained from the UCSC genome browser[27]). The non-target guide oligonucleotide was designed as a scramble DNA sequence that does not match the rat genome. Oligonucleotides are obtained (University of Utah DNA/Peptide Synthesis Core), hybridized, phosphorylated and cloned into gRNA expressing plasmids (addgene plasmid 47108) using BbsI sites. To produce a lentiviral vector that co-expresses dCAS-KRAB-T2A-GFP and gRNA, gRNA cassette are cloned via PCR and inserted into 3^(rd) generation lentiviral transfer vector that expresses dCas-KRAB-T2A-GFP under the control of the human UbC promoter via BsmBI sites. To produce transduction media (DMEM), epigenome editing vector constructs were produced in HEK 293T cells using a previously reported method[49] and stored at −80° C. until use. For transduction of rat DRG neurons, media were removed and replaced with transduction media supplemented with polybrene (8 μg/ml) and cells were cultured for 24 hours. The next day, viral media was removed replaced with fresh SATO-medium. Transduced DRG neurons were cultured in SATO-medium under standard cell culture conditions until experiments were performed.

AKAP 150 Quantitative Reverse-Transcription PCR.

Four days following transduction, cells were harvested for total RNA using the PureLink RNA microscale kit (LifeTech). cDNA synthesis was conducted using the High Capacity cDNA RT kit (Lifetech). qRT-PCR using Taqman Universal PCR Master Mix (LifeTech) was performed with the TaqMan Gene Expression Detection Assay (LifeTech) with oligonucleotide primers for AKAP 150 and GAPDH. Results are expressed as fold increase in mRNA expression of AKAP 150 normalized to GAPDH expression using the ΔΔ C_(t) method.

AKAP Epigenome Edited Neuron Sensitization.

DRG neurons were transduced with epigenome editing lentiviral constructs targeting the AKAP 150 gene promoter region or a non-target gRNA, as described above, and cultured in SATO-medium for 4 days following removal of lentivirus. Successful transduction was verified via fluorescent imaging of GFP in transduced neurons. Following the culture period, transduced and naïve (non-transduced) DRG neurons were exposed to degenerative IVD conditioned media or control media (DMEM) and incubated for 24 hours. Following incubation, neurons were loaded with the calcium indicator dye rhod-2AM (Molecular Probes, 3 μM) and incubated in the dark at 37° C. for 1 hour. Fluorescent measurements of calcium were performed using a multi-photon microscope (Bruker/Prairie View, excitation 1105 nm, emission 585 nm, 0.5 Hz). Neurons were incubated at 37° C. for 15 minutes to establish a baseline calcium signal and then exposed to heat stimuli of 38, 39, 40, 42, and 44° C. for two minutes while imaging. Cells were returned to the baseline temperature for 5 minutes between exposures to elevated temperatures.

Curve Fitting of Neuron Firing.

Data from the conditioned media and IL-6 blocking experiments were fit to the sigmoidal Boltzmann equation:

$\begin{matrix} {y = {\min + \frac{\left( {\max - \min} \right)}{1 + {\exp\left( \frac{T_{50} - x}{slope} \right)}}}} & \lbrack 2\rbrack \end{matrix}$

with the percentage of neurons firing plotted as a function of temperature. Each trial was individually fit to produce values for T50 and max. T50 was defined as the temperature at which 50 percent of the maximum response occurs. The max was defined as the maximum percentage of neurons firing predicted by the curve fitting.

Statistical Analysis.

Degenerative IVD conditioned media exposure and IL-6 blocking experiment data were analyzed by two-way analysis of variance (ANOVA) on repeated measures with Tukey's post hoc test, treating media condition and temperature as factors. AKAP inhibitor experiment data, T50 and maximum response data from IL-6 blocking experiments were analyzed by one-way ANOVA with Tukey's post hoc test, treating media condition as the factor. Degenerative IVD pH level experiment data were analyzed by two-way ANOVA with Tukey's post hoc test, treating media condition and temperature as factors. Significance was tested at α=0.05 for all statistical analyses.

Results

Degenerative IVD Conditioned Media Triggers Sensitization of DRG Neurons to Heat Simuli.

The percentage of rat DRG neurons firing when exposed to degenerative IVD conditioned media was significantly elevated over the neurons firing in the control media group (p<0.05) and healthy IVD conditioned media group (p<0.05) at temperatures as low as 38° C. (FIG. 2A). In addition, the percentage of neurons firing when exposed to healthy IVD conditioned media was similar to the percentage of neurons firing in the control media group at all temperatures tested (FIG. 2A).

The percentage of neurons firing as a function of temperature was well defined by curve fitting the data to the Boltzmann equation for the control media (r²=0.97±0.02), healthy IVD conditioned media (r²=0.97±0.03), and degenerative IVD conditioned media (r²=0.97±0.02) treatment groups (FIG. 2A). The T50, the temperature at which half the maximum firing response occurs, and maximum firing response were calculated via Boltzmann equation fits to each trial. The T50 value of neurons exposed to thermal stimuli in the presence of degenerative IVD conditioned media (38.25° C.±0.77) was significantly lower than the T50 values in both the control media (39.25° C.±0.13, p<0.05) and the healthy IVD conditioned media treatment groups (39.12° C.±0.38, p<0.05)(FIG. 2B). In addition, the maximum firing response of neurons exposed to thermal stimuli in the presence of degenerative IVD conditioned media (73.69%±6.5) was significantly greater than the maximum response in the control media (52.69%±9.42, p<0.05) and healthy IVD conditioned media treatment groups (51.25%±11.58, p<0.05)(FIG. 2C).

IL-6 is the Primary Mediator of Sensitization of DRG Neurons by Degenerative IVD Conditioned Media.

The results from the original sensitization experiments were repeated and confirmed as the percentage of rat DRG neurons firing when exposed to heat stimuli in the presence of degenerative IVD conditioned media was significantly elevated (p<0.05) when compared to the percentage of neurons firing in the control media group at temperatures as low as 38° C. (FIG. 3A). When rat DRG neurons were exposed to heating in the presence of degenerative IVD conditioned media supplemented with IL-6 blocking antibody, the firing response returned to control media levels (p=1.0) for all temperatures tested (FIG. 3A) and was significantly less (p<0.05) than the percentage of neurons firing in the degenerative IVD conditioned media group at all temperatures above 38° C. (FIG. 3A). In contrast, addition of the isotype control antibody had no effect on firing response compared to degenerative IVD conditioned media group (p=0.895) (FIG. 3A). Furthermore, the IL-6 sensitization effect was seen in all patients tested, as all patients showed a decreased (p<0.05) firing response after IL-6 blocking antibody exposure (FIGS. 3A, D).

The number of neurons firing as a function of temperature was well defined by curve fitting the data to the Boltzmann equation for the control media (r²=0.97±0.02), degenerative IVD conditioned media (r²=0.97±0.02), IL-6 blocking antibody (r²=0.98±0.02), and isotype control antibody (r²=0.94±0.04) treatment groups (FIG. 3A). The T50 and maximum firing response were calculated via Boltzmann equation fits to each trial. The T50 value of neurons exposed to heat stimuli in the presence of conditioned media supplemented with IL-6 blocking antibody (39.53° C.±0.4) returned to control media levels (39.25° C.±0.13, p=0.993) and was significantly greater than the T50 values of neurons in both the conditioned media (38.25° C.±0.77, p=0.004) and isotype control antibody groups (38.16° C.±0.4, p=0.003) (FIG. 3B). In addition, the maximum firing response of DRG neurons exposed to heat stimuli in the presence of conditioned media supplemented with IL-6 blocking antibody (44.6%±11%) returned to control media levels (52.7%±9.4%, p=0.534) and is significantly less than the maximum firing response of neurons in the conditioned media (73.7%±6.5%, p<0.0001) and isotype control antibody groups (66%±2.8%, p=0.001) (FIG. 3C).

Inhibition of AKAP Abolishes IL-6 Mediated Sensitization of Rat DRG Neurons by Degenerative IVD Conditioned Media.

Sensitization by degenerative IVD conditioned media was once again confirmed as the percentage of DRG neurons firing at 39° C. exposed to degenerative IVD conditioned media (59.72%±18.9%) was significantly greater (p=0.007) than the percentage of neurons firing in the control group (14.36%±2.3%, FIG. 4). When neurons were exposed to degenerative IVD conditioned media in the presence of the AKAP inhibitor St-Ht31, the percentage of neurons firing returned to baseline levels (15.51%±2.7%) and was not significantly different from the control media group (p=0.998, FIG. 4). In addition, the percentage of neurons firing in the degenerative IVD conditioned media supplemented with the control peptide St-Ht31P (61.91%±13.9%) was significantly greater than the control media (p=0.006) and the St-Ht31 groups (p=0.006), but not significantly different from the degenerative IVD conditioned media group (p=0.996, FIG. 4).

FIG. 4 shows the results of the experiments described above as a percentage of rat DRG neurons firing exposed to 39° C. in the presence of control media, degenerative IVD conditioned media, degenerative IVD conditioned media supplemented with the AKAP inhibitor peptide St-Ht31 (50 μM) or degenerative IVD conditioned media supplemented with the control peptide St-Ht31P (50 μM). n=3 for all groups tested.

Degenerative IVD Conditioned Media and Pathological Acidic pH Levels Synergistically Enhance Sensitization of Rat DRG Neurons to Heat Stimuli and Trigger Spontaneous Neuron Firing.

The percentage of rat DRG neurons firing when exposed to pH 6.5 degenerative IVD conditioned media was significantly elevated (p<0.05) over all other media conditions tested at 37° C., 38° C., and 39° C. At 37° C., spontaneous neuron firing occurred in neurons in the pH 6.5 degenerative IVD conditioned media group (13±4.2%, FIG. 5), which had not been observed in any other experiment or group tested.

The T50 values of neurons in the pH 6.5 degenerative IVD conditioned media group (37.32±0.39° C., p=0.02, FIG. 5B) was significantly decreased compared to the degenerative IVD conditioned media (38.48±0.28° C.), the pH 6.5 control media (39.76±0.76° C., p=0.01), and the control media (39.62±0.24° C., p=0.02) groups (FIG. 5).

FIG. 5 shows the results from the experiments described above as the percentage of rat DRG neurons firing exposed to heat stimuli in the presence of control media (pH 7.4 degenerative IVD conditioned media (pH 7.4), or pH 6.5 degenerative IVD conditioned media (n=4) *=p<0.05 when compared to the control media group, #=p<0.05 when comparing pH 6.5 degenerative IVD conditioned media group to degenerative IVD conditioned media group (pH 7.4).

Epigenome Editing of AKAP Promoter in Rat DRG Neurons Abolishes Degenerative IVD Mediated Sensitization of Rat DRG Neurons.

Transduction of DRG neurons with CRISPR epigenetic editing lentiviral vectors targeting AKAP 150 (FIG. 6C) regulated expression of AKAP 150 (FIG. 6D) with AKAP guide 4 exhibiting maximum down-regulation when compared to DRG neurons transduced with non-target lentiviral vectors (21.03% of non-target expression, p<0.05).

The percentage of neurons firing in naïve (non-transduced) neurons and neurons receiving non-targeting lentiviral vectors subjected to thermal stimuli in the presence of degenerative IVD conditioned media were significantly elevated when compared to the control media group (p<0.05) at all temperatures tested. When AKAP 150 epigenome edited neurons were exposed to degenerative IVD conditioned media, the percentage of neurons firing returned to baseline levels (FIG. 6E) and were not significantly different from control media levels. From the curve fitting, the T50 value of AKAP egigenomically edited neurons exposed to degenerative IVD conditioned media (38.7±0.29° C.) was significantly lower than T50 value of naïve (37.94±0.07° C., p=0.003) and non-target epigenomically edited neurons (38.7±0.29° C., p=0.01), yet not significantly different from the control media group (38.99±0.39° C., p=0.3298)(FIG. 6F). The maximum response of AKAP epigenomically edited neurons exposed to degenerative IVD conditioned media (50.63±6.59%) returned to control levels (51.12±8.02%, p=0.9959) and was significantly decreased compared to the maximum response of naïve (74.48±11.06%, p=0.001) and non-target epigenomically edited neurons (69.14±4.93%, p=0.001) exposed to degenerative IVD conditioned media (FIG. 6G).

Discussion

The interactions between the degenerative IVD environment (inflammatory cytokines and pH) and peripheral neurons were modeled and investigated to provide insight into the underlying mechanisms of discogenic back pain. The data presented herein demonstrates that degenerative IVD produces specific factors/cytokines capable of directly sensitizing DRG neurons to heat stimuli and that sensitization is enhanced at pH levels experienced by neurons in the degenerative IVD. This sensitization led to spontaneous firing of neurons and a T50 firing threshold (37.32±0.39° C.) near resting core body temperature, but was not observed in unconditioned media or media conditioned with healthy IVD. Blocking IL-6 in the conditioned media abolished the entirety of this sensitization, and sensitization was also abolished after inhibiting AKAP 150, indicating sensitization occurs through the IL-6/AKAP/TRPV1 pathway. Once the IL-6/AKAP/TRPV1 pathway was established as mediating sensitization, the ability of CRISPR epigenome editing of peripheral neurons to regulate sensitization was investigated. This data demonstrates that epigenome editing of AKAP 150 expression in rat DRG neurons abolishes degenerative IVD sensitization of neurons to thermal stimuli while these neurons maintain their non-pathological firing response. Together, these results implicate the synergistic effects of acidic pH and the activation of the IL-6/AKAP/TRPV1 as the underlying mechanism for degenerative IVD induced neuron sensitization, demonstrates CRISPR epigenomic editing of AKAP expression regulates neuron sensitization and establishes CRISPR epigenome editing of nociceptive neurons as a possible treatment strategy for discogenic pain.

Factors released from degenerative IVDs sensitize DRG neurons to noxious stimuli, particularly heating were demonstrated. Previous studies have demonstrated increased cytokine levels (e.g. TNF-α, IL-1β, IL-6, and IL-8) in painful IVDs[10,36,37,52,53] and that inflammatory cytokines are capable of sensitizing rodents to thermal and mechanical stimuli in the paw in models of radiculopathy and peripheral neuropathy [5,42,45]. The findings disclosed herein demonstrate an ability for the degenerative IVD conditions, but not healthy IVD tissue, to directly lead to afferent neuron sensitization. These findings support the hypothesis that inflammation driven sensitization of nociceptive neurons in the degenerative IVD could contribute to discogenic back pain via sensitization and establish an in vitro model, which can be used to study these interactions and screen novel therapeutics.

In this study, the degenerative IVD conditioned media combined with acidic pH was capable of inducing spontaneous neuron firing and sensitizing afferent neurons to noxious stimuli at temperatures as low as 37° C. Under these sensitized conditions, the T50 value (37.3° C.) falls within the normal core body temperature range (36.1-37.8° C.) and the maximum response is observed just above this range (38° C.), with 13% of neurons spontaneously firing at the mean core temperature of 37° C. Since the majority of neurons innervating the IVD are nociceptive neurons that co-express CGRP and TRPV1, a pathological ability for TRPV1 channels to fire at sub 38° C. temperatures would provide a mechanism for nociceptive signaling in the degenerative IVD. This data suggests that TRPV1 in the disc may play a role in discogenic back pain due to synergistic pH and inflammatory cytokine mediated sensitization.

This data indicates that IL-6 is the main mediator of the neuron sensitization observed after exposure to degenerative IVD conditioned media. Multiple inflammatory cytokines have been observed in the pathological IVD, which includes TNF-α, IL-1β, IL-6, and IL-8[10,36,37,52,53]. IL-1β and TNF-α[35,36,51] are the most common cytokines investigated in disc pathology due to their role in extracellular matrix breakdown and implication in rodent models of radiculopathy. TNF-α, IL-1β and IL-6 have all been hypothesized to contribute to discogenic back pain; however, this data demonstrates that blocking IL-6 action in the degenerative conditioned media abolished the thermal sensitivity and demonstrated IL-6 as a main mediator of inflammatory sensitization of neurons in these experiments and not TNF-α or IL-1β. Furthermore, IL-6 dependent sensitization was observed in neurons exposed to conditioned media from all patients tested suggesting the same mechanism may exist in the larger patient population. It's important to note that DRG neurons do not express membrane bound IL-6 receptor but rather IL-6 signals via trans-signaling through a complex formed by IL-6, soluble IL-6 receptor and gp130[1,42]. This implicates trans-signaling as a possible contributor to discogenic back pain and may indicate the IL-6/sIL-6R/gp130 complex as a primary target for therapeutic development for the treatment of discogenic back pain.

IL-6 induced sensitization in peripheral neuropathy and arthritis models has been observed due to increased phosphorylation of heat-sensitive ion channels, which causes channel activation at lower temperatures, an increased expression of heat-sensitive ion channels in sensitized neurons, or a combination of the two mechanisms. TRPV1 is a heat sensitive ion channel[12] expressed in nociceptive DRG neurons[6] that has demonstrated involvement in IL-6 induced thermal hyperalgesia in neuropathy models and can be sensitized via phosphorylation by Protein Kinase A (PKA) or Protein Kinase C (PKC)[22,23]. The phosphorylation of TRPV1 by PKA/PKC is regulated by AKAP 150/79 (79 is human and 150 is the rodent analog)[22,23], a scaffolding protein, that is co-expressed and co-localized with TRPV1 in DRG neurons [8,22] and mediates TRPV1 phosphorylation by facilitating interactions between PKA/PKC and TRPV1. As a result, the role of TRPV1 sensitization was investigated via phosphorylation by inhibiting AKAP 150 via the inhibitor peptide St-HT31[23]. When blocking the PKA/PKC binding site on AKAP 150 with the inhibitor peptide St-HT31, the observed neuronal thermal sensitivity induced by degenerative IVD was abolished. These results indicated that AKAP150/TRPV1 interaction was required for thermal sensitization of neurons and was the primary mechanism for IL-6 induced sensitization by degenerative IVD. Additionally, the abolition of IL-6 induced thermal sensitization by inhibiting AKAP 150/TRPV1 interaction establishes AKAP 150/79 as a potential therapeutic target in discogenic back pain.

The results show that lentiviral CRISPR epigenome editing of nociceptive neurons inhibits degenerative IVD sensitization to noxious stimuli, particularly heating. CRISPR based epigenome editing allows for the local, long-term, stable site directed gene repression by H3K9 histone methylation. It was hypothesized that degenerative IVD induced sensitization of neurons could be regulated by epigenome editing pain sensitization pathway genes in nociceptive neurons. The data demonstrate that sensory neurons with epigenome modification of AKAP 150 expression in sensory neurons maintained a normal firing response under conditions that sensitize non-edited neurons to noxious stimuli. These results demonstrate epigenome editing of pain related genes in nociceptive neurons regulates sensitization and establishes epigenome modification of pain pathway genes in nociceptive neurons as a therapeutic strategy for discogenic back pain treatment.

In this study, it was demonstrated that pH, at degenerative IVD levels, and degenerative IVD released factors (IL-6) synergistically sensitize TRPV1 channels to fire at sub 38° C. temperatures through the IL6/AKAP/TRPV1 signaling pathway, which would provide a mechanism for nociceptor firing in the degenerative IVD environment. In addition, it was demonstrated that epigenome editing of AKAP expression in sensory neurons prevented degenerative disc environment triggered neuron sensitization to noxious stimuli. These results elucidate a therapeutic target and establish epigenome editing of nociceptive neurons as a treatment strategy for discogenic back pain.

Example 2: CRISPR Based Epigenome Editing of Inflammatory Receptors for the Promotion of Cell Survival and Tissue Deposition in Inflammatory Environments

Materials and Methods

Plasmids, Guide Design and Cloning.

Using the UCSC genome browser (GRCh37/hg19), the 5-UTR and the promoter region, 1000 base pairs upstream were selected and input into the CRISPR design tool (crispr.mit.edu). This tool outputs 20 bp gRNAs that are followed on their 3′ end by the PAM sequence NGG, which is specific to the CRISPR-Cas9 system derived from Streptococcus pyogenes. Additionally, the CRISPR design tool scores the potential gRNA sequences based on the number of off-target sites they have and how many are within genes (e.g., higher score means less off-target sites). From this list, the highest scoring gRNAs were input into the BLAT tool of the UCSC genome browser to inspect for overlap of gRNAs with DNAse hypersensitivity peaks, therefore narrowing down potential gRNAs. With these criteria, 5-6 gRNAs were selected for TNFR1 and IL1R1 (Table 3. These selected gRNAs were synthesized (University of Utah peptide synthesis core), annealed, phosphorylated and ligated into hU6-gRNA plasmids at the BbsI sites. For each gene two high performing U6-gRNA cassettes were PCR amplified and transferred into the S. pyogenes dCas9 expressing repression lentiviral vector (hUbC-dCas9-KRAB-T2A-GFP) upstream of the hUbC promoter at the Esp3I sites. An NF-kB reporter plasmid was obtained from Addgene (49343) for experiments assaying NF-kB activity.

TABLE 3 Target sequences for each gene and the control. Target SEQ ID Gene Name Sequence NO. TNFR1 gRNA 1 5′-CAGTGTTGCAACAGCGGGAC-3′  1 TNFR1 gRNA 2 5′-AGACTCGGGCATAGAGATCA-3′  2 TNFR1 gRNA 3 5′-GAATGGCAGGCACCCAGTCA-3′  3 TNFR1 gRNA 4 5′-ATAAGCGTCCGACACATGAT-3′  4 TNFR1 gRNA 5 5′-GCAAGGGGCTTATTGCCCCT-3′  5 IL1R1 gRNA 1 5′-GGAGTCGCCAACTCAATTCG-3′  6 IL1R1 gRNA 2 5′-TGGGGTCCTTGGGCGACTGC-3′  7 IL1R1 gRNA 3 5′-AGAGGCATTTCCCGGACTCG-3′  8 IL1R1 gRNA 4 5′-AGCACAAAGTTGGCTGCGCC-3′  9 IL1R1 gRNA 5 5′-GGGAGGTGACACCCAGTTTA-3′ 10 IL1R1 gRNA 6 5′-AAAGTAGCCTGACGTATCCG-3′ 11 N/A Nontarget 5′-TTTTTAATACAAGGTAATCT-3′ 12 gRNA

TABLE 4 Guide RNA sequences for each gene and the control Target SEQ ID Gene Name Sequence NO. TNFR1 gRNA 1 5′-CAGUGUUGCAACAGCGGGAC-3′ 79 TNFR1 gRNA 2 5′-AGACUCGGGCAUAGAGAUCA-3′ 80 TNFR1 gRNA 3 5′-GAAUGGCAGGCACCCAGUCA-3′ 81 TNFR1 gRNA 4 5′-AUAAGCGUCCGACACAUGAU-3′ 82 TNFR1 gRNA 5 5′-GCAAGGGGCUUAUUGCCCCU-3′ 83 IL1R1 gRNA 1 5′-GGAGUCGCCAACUCAAUUCG-3′ 84 IL1R1 gRNA 2 5′-UGGGGUCCUUGGGCGACUGC-3′ 85 IL1R1 gRNA 3 5′-AGAGGCAUUUCCCGGACUCG-3′ 86 IL1R1 gRNA 4 5′-AGCACAAAGUUGGCUGCGCC-3′ 87 IL1R1 gRNA 5 5′-GGGAGGUGACACCCAGUUUA-3′ 88 IL1R1 gRNA 6 5′-AAAGUAGCCUGACGUAUCCG-3′ 89 N/A Nontarget 5′-UUUUUAAUACAAGGUAAUCU-3′ 90 gRNA

Cell Culture.

HEK293T cells and immortalized hADMSCs were obtained from the American Tissue Collection Center (ATCC). HEK293T cells were cultured in high glucose DMEM (Gibco) supplemented with 10% FBS (Hyclone) and 5 μg/mL gentamicin and subcultured according to manufacturer's instructions. Human ADMSCs were cultured in mesenchymal stem cell basal medium (ATCC, PCS-500-300), supplemented with the ADMSC growth kit (ATCC, PCS-500-40) and 25 μg/mL gentamicin and subcultured according to manufacturer's instructions. All cell cultures were maintained at 37° C. with 5% CO₂ with media changed every 2-3 days.

Lentivirus Production.

Production of lentivirus was performed in HEK293T cells. Prior to plating cells, 6-well culture dishes were pretreated with 0.001% poly-1-lysine for one hour, rinsed 2× with PBS and air dried. Once pretreated dishes were ready, HEK293T cells were plated at a density of 600,000 cells/well in high glucose DMEM (Gibco) supplemented with 10% FBS in 6-well plates. The next day cells were cotransfected with 4 μg of the appropriate lentiviral vector, 3 μg of the packaging plasmid psPAX2 (Addgene, 12260), and 1.2 μg of the envelope plasmid pMD2.G (Addgene, 12259) using lipofectamine 2000. After 16-20 hours the transfection medium was removed and replaced with 2 mL of fresh medium. Supernatant containing lentivirus was collected 24 and 48 hours after removal of transfection medium and filtered through a 0.45 μm PVDF filter. Virus was immediately aliquoted and frozen at −80° C. after filtration until use.

Measurement of Regulation of Gene Expression.

Production of Stable Cell Lines.

Cells were plated at a density of either 400,000 cells/well (HEK293T cells) or 200,000 cells/well (hADMSCs) in 6-well plates in respective expansion media and allowed to adhere overnight. The next day 1 mL of lentivirus, supplemented with polybrene at a concentration of 8 μg/mL, was placed on cells. After 24 hours virus was removed and washed with PBS 5 times to remove remains of lentivirus. Cells were cultured or frozen down until use. Regarding dCas9-KRAB expressing cells, cells were sorted via flow cytometry using a FACS Aria Cell Sorter to select for GFP positive cells. Cells were cultured or frozen down until use.

Quantitative Reverse Transcriptase PCR.

Total RNA was harvested from cells using Purelink RNA mini kit (Ambion). Purified RNA subsequently digested with amplification grade DNAse I (applied biosystems) according to the manufacturer's protocol and then cDNA synthesis was performed with DNAse I digested RNA using the High-Capacity cDNA Reverse Transcription Kit with RNase Inhibitor (Applied Biosystems, 4374966). Following cDNA synthesis qPCR was formed using Taqman gene expression assays using best coverage primers for each gene (Hs01042313_m1, Hs00991002_m1). Changes in gene expression were expressed as fold changes in mRNA expression relative to the nontarget control, and normalized to GAPDH mRNA expression, using the ΔΔC_(t) method.

Guide RNA Screening in HEK293T Cells.

HEK293T cells stably expressing dCas9-KRAB GFP were seeded in 6-well plates at a density of 600,000 cells/well in DMEM-HG with 10% FBS. The following day 2 μg of each gRNA plasmid (one gRNA per well, n=3) was transfected into the cells using lipofectamine 2000 according to manufacturer's instructions. Forty-eight hours post transfection RNA was isolated, DNase I digested and used for cDNA synthesis. Subsequently each sample was then run through taqman qPCR using primers for TNFRSF1A or IL1R1 and housekeeping gene GAPDH to quantify downregulation of each gene by each guide. Gene downregulation was quantified using the ΔΔCt method to characterize fold change relative non-target gRNA expressing cells.

Measurement of Functional Effects of Epigenome Editing Based Gene Downregulation.

NF-κB Activity Assays.

HEK293T cells and hADMSCs were transduced with the earlier mentioned NF-κB reporter vector and analyzed for changes in NF-κB activity in response to dosing cells with TNF-α/IL-1β (RnD systems, ProSpec). To further describe, cells expressing the NF-κB reporter were plated in white 96-well plates (HEK293T cells at 25,000 cells/well and hADMSCs at 5000 cells/well) and allowed to attach overnight. The next day cells were dosed with the appropriate amounts of inflammatory cytokines (0, 150, 1, and/or 10 ng/mL of TNF-α/IL-1β) for 24 hours. At 24 hours luminescence corresponding to NF-κB activity was measured in one set of cells using the bright glo assay (Promega) and cell number was measured on another set of cells under the same treatment using the real-time glo assay (Promega). Changes in NF-κB activity were quantified as a fold change in luminescence relative to the no dose control for each cell type, with NF-κB activity normalized to cell number.

Three Dimensional Culture Under Inflammatory Conditions.

Human ADMSCs were cultured in pellet cultures within the presence of TNF-α/IL-1β to observe matrix production and cell proliferation under inflammatory conditions. Three dimensional culture media consisted of DMEM-HG (thermofisher), insulin (5 μg/mL), transferrin (5 μg/mL), selenous acid (5 ng/mL), 1.25 mg/mL BSA, 0.17 mM ascorbic acid 2-phosphate, 0.35 mM proline, 0.1 μm dexamethasone, 10 ng/mL TGFβ-3 (ProSpec) and 1% antibiotic/antimycotic (unless specified all reagents were purchased from Sigma). To create cell pellets, cells were trysinized, resuspended at a density of 1×10⁶ cells/mL, and 200 μL aliquots were placed in single wells within a polypropylene v-bottom plate and spun at 1000 g for five minutes to create pellets at the bottom of each well. Pellets formed and lifted after 24 hours at which media was replaced and dosing with TNF-α/IL-1β was begun. Pellets were cultured for 28 days with media changed every 3 days after which pellets were either fixed in 10% NBF or frozen at −80° C. until analysis.

Size Analysis.

Prior to pulling pellets for analysis, pellets were imaged while still in wells. Images were used to perform cross sectional area analysis of pellets in ImageJ (world wide address: imagej.nih.gov/ij/). Cross sectional area measurements were converted from pixel² to mm² using a reference object of known size.

Chondrogenesis Under Inflammatory Conditions.

Human ADMSCs were differentiated in pellet cultures dosed with TNF-α or IL-1β to investigate ability to undergo chondrogenesis under inflammatory conditions. Basal chondrogenic media consisted of DMEM-HG (thermofisher), 1×ITS+ premix (Corning), 0.1 μM dexamethasone, 0.17 mM, 0.35 mM ascorbic acid 2-phosphate, 1× antibiotic antimycotic solution (unless specified all reagents were purchased from Sigma). To create complete differentiation media, basal chondrogenic media was supplemented with 10 ng/mL of TGFβ-3 and BMP-6 (Peprotech). To create chondrogenic pellets, cells were trysinized, resuspended in basal chondrogenic media at density of 1.25×10⁶ cells/mL and 200 μL, aliquots (250,000 cells) were placed in single wells within a polypropylene v-bottom plate (Corning) and spun at 1000 g for five minutes to create pellets at the bottom of each well. Pellets formed and lifted after 24 hours after which media was replaced with complete chondrogenic media with added TNF-α/IL-1β to respective wells. Pellets were cultured for 21 days with media replaced every 3 days after which pellets were either fixed in 10% NBF or lyophilized and frozen at −80° C. until analysis. Spent media was collected at each media change for analysis of glycosaminoglycan (GAG) content released.

DNA and Glycosaminoglycan Quantification.

Pellet cultures were analyzed for DNA and GAG content. Prior to analysis samples were papain digested at 60° C. for 12-16 hours in 0.125 μg/mL papain in 0.10 M Na₂HPO₄, 0.010 M Na₂EDTA, and 0.01 M L-cysteine hydrochloride (pH 6.5). DNA content was then measured using the Hoechst 33258 assay. Briefly, digested sample was added to Hoechst dye solution (0.1 μg/mL of Hoechst 33258 in 10 mM Tris, 1 mM disodium EDTA, and 0.1 mM NaCl at pH 7.4) and fluorescence was measured on a Biotek Synergy HTX plate reader. DNA concentration was based on standard curves made using calf thymus DNA (Sigma). Glycosaminoglycan content of the papain digested pellets was analyzed using the DMMB assay as previously described (Zheng and Levenston, 2015). Briefly samples were added to DMMB solution (pH 1.5) and the absorbance was measured at 525 and 595 nm and the OD₅₂₅₋₅₉₅ was used to determine concentration. Concentration was based on standard curves were made using shark chondroitin-6-sulfate (Sigma).

Histology.

Samples were fixed in 10% NBF for 48 hours and then transferred to 70% EtOH and taken to the University of Utah histology core for further processing and embedding. Samples were paraffin embedded and 5 μm sections were mounted onto charged slides. Samples were rehydrated and stained with H&E to characterize matrix production. Slides were imaged using light microscopy (Nikon Eclipse E400, Olympus UC50 Camera) to visualize sample variability under multiple conditions.

Characterization of Immunomodulatory Properties of Engineered ADMSCs.

To investigate immunomodulatory properties of engineered hADMSC lines, their suppressive effect on phytohemagglutinin (PHA) activated PBMCs in co-culture was characterized. Prior to co-culture hADMSCs were Mitomycin C treated (10 μg/mL) for 2 hours at 37 C. After treatment hADMSCs were rinsed 2× with PBS, trypsinized and plated at a density of 12,800 cells/well in a 96-well plate in RPMI1640 media (thermofisher) supplemented with 10% FBS and 100 U/mL penicillin, and 0.1 mg/mL streptomycin. The following day PBMCs (ATCC) were added at a density of 102,400 cells/well (1:8 hADMSC:PBMC ratio) and active with 5 μg/mL PHA. After two days of coculture EdU was added at a concentration of 10 μM and after 18 hours PBMCs were harvested for analysis. To analyze proliferation PBMCs were CD45 stained (BD biosciences) and EdU labeled with the Click-iT EdU flow cytometry kit (thermofisher) according to manufacturer's instructions. The amount of EdU positive CD45 labeled PBMCs were characterized by flow cytometry to provide a quantitative measurement of proliferation compared to the control of PBMCs cultured alone.

Statistical Analysis.

Experiments characterizing efficiency of gRNAs in downregulating gene expression were analyzed by one-way analysis of variance (ANOVA) with Tukey's post hoc test, treating different gRNAs as factors. Experiments looking at changes in NF-κB activity, pellet size, DNA content and GAG content were analyzed by two-way ANOVA with Tukey's post hoc test, treating different cell types and cytokine dose as factors. Experiments investigating immunosuppressive effects were analyzed by one-way analysis of variance (ANOVA) on repeated measures with Tukey's post hoc test, treating different types of hADMSCs as factors.

Results

Epigenome Editing of TNFR1 in HEK293T Cells Efficiently Downregulates NF-κB Activity.

Designed gRNAs were initially tested in HEK293T cells to screen for the most efficient gRNAs and provide proof of concept in signaling regulation. Screening of 5-6 gRNAs for both TNFR1 and IL1R1 demonstrated efficient gene downregulation by multiple gRNAs (FIG. 7) with up to 87% gene downregulation by gRNA 1 for TNFR1 and 67% gene downregulation by gRNA 1 for IL1R1. Downregulation of TNFR1 signaling by gRNA 1, measured after 24 hours of dosing with 0, 0.15, 1, and 10 ng/mL of TNF-α demonstrated effective inhibition of TNFR1 signaling. This was noted by significant decreases in NF-κB activity (up to 95%) with no significant increase in NF-κB activity at the lowest most physiologically relevant dose of 0.15 ng/mL.

Epigenome Editing of TNFR1 and IL1R1 in hADMSCs Downregulates NF-κB Activity.

Testing for gene downregulation by two gRNAs, verified to be efficient in HEK293T cells, in hADMSCs demonstrated up to 90% and 88% gene downregulation of TNFR1 and IL1R1, respectively, thus, demonstrating efficient epigenome editing across multiple cell types (FIG. 8). Of note, efficiency by gRNAs flipped for IL1R1 in comparison to data shown in HEK293T cells; therefore, demonstrating how small genetic differences in the promoter sites can have a large effect on the efficacy of gene regulation.

Measurement of NF-κB activity post cytokine dosing in hADMSCs demonstrated potent downregulation of TNFR1 signaling, with no significant increase in NF-κB activity noted at both doses of TNF-α (FIG. 8). Downregulation in signaling of IL1R1 was present but not as potent, while significant NF-κB activity was decreased at the 0.15 ng/mL dose of IL-1β (40% decrease, FIG. 8). Overall regulation of signaling was present in these cells, therefore, demonstrating regulation of TNFR1 and IL1R1 at signaling level and not just at the gene level.

TNFR1/IL1R1 Epigenome Editing Protects hADMSCs from an Inflammatory Environment.

Three dimensional culture of hADMSCs in the presence of TNF-α and IL-1β, demonstrated overall cell protection when the cytokine's respective receptor was downregulated. Measurement of cell pellet cross sectional area demonstrated the maintenance of size in TNFR1/IL1R1 edited vs non-target edit cells, therefore, indicating protection from matrix breakdown (FIG. 9). H&E staining of cell pellets further demonstrated this with lighter background staining in non-target edit control hADMSCs pellets dosed with IL-1β/TNF-α (FIG. 9). Additionally, examining DNA content relative to control, TNFR1 edited cells demonstrated significantly improved maintenance of DNA content compared to nontarget edit cells (FIG. 9).

When induced to undergo chondrogenic differentiation by TGFβ3 and BMP-6, both edited and unedited cells underwent chondrogenic differentiation as noted by significant amounts of measured GAG content. When dosed with either TNF-α or IL-1β in chondrogenic media, chondrogenesis was inhibited in naïve and non-target edit control hADMSCs as noted by significant decreases in GAG content relative to undosed controls (FIG. 10). Looking specifically at GAG/pellet, significant decreases were seen in all samples but the decrease was less in TNFR1 edited cells. When observing GAG within spent media TNFR1 edited cells did not show a significant decrease in GAG released while all other cell types did. Observing total GAG content, TNFR1 edited cells showed no significant decrease in overall GAG content whereas all other cell types did. Therefore this data indicates that epigeneome editing based downregulation TNFR1 expression allows hADMSCs to differentiate in an environment with elevated levels of TNF-α while IL1R1 downregulation still allows IL-1β to have an inhibitory effect on chondrogenesis.

Immunomodulatory Properties of hADMSCs are Maintained Post Epigenome Editing.

Co-culture of hADMSCs with PBMCs demonstrated that therapeutic immunomodulatory properties of these stem cells are maintained after epigenome editing (FIG. 11). Relative to naïve untransduced hADMSCs, PBMCs cultured with TNFR1 edited hADMSCs showed no significant increase in proliferation therefore indicating that immunomodulatory properties are well maintained. PBMCs cultured with IL1R1 edited hADMSCs showed a slight but significant decrease in suppression of PBMC proliferation therefore indicating a decrease in immunomodulation. Overall, there was still a 40% decrease in PBMC proliferation by IL1R1 edited hADMSCs relative to PBMCs alone; therefore, beneficial immunomodulatory properties are still present.

Example 3: Investigating CRISPi Cell-Engineering Methods for Treatment of Intervertebral Disc Degeneration

Methods

CRISPRi Vector Design.

Sequences for gRNAs for the TNFR1 and ILIR1 promoter region of each gene were selected along with an adjacent protospacer adjacent motif (crispr.mit.edu). A non-targeting gRNA was chosen as a control. Each gRNA was cloned into a plasmid under the control of the U6 promoter. To screen the gRNAs for the best knockdown, gRNA plasmids were transfected into a Human Embryonic Kidney (HEK293T) cell line stably expressing dCas9-KRAB (Lipofectamine 2000, n=3 per guide). Forty-eight hours post-transfection, RNA was isolated and quantitative reverse transcriptase PCR (qRT-PCR) was performed for TNFR1, IL1R1, and GAPDH. For TNFRI, the gRNA showing the greatest knockdown was cloned into two different lentiviral vectors, resulting in the co-expression of the gRNA with dCas9-T2A-GFP or dCas9-KRAB-T2AGFP from a single lentiviral vector.

Human NP Cell CRISPRi.

Human nucleus pulposus (NP) cells were obtained from a 51-year-old male discectomy patient and transduced with the TNFR1 lentiviral CRISPRi vectors along with a control lentiviral vector that did not express a gRNA. Quantitative RT-PCR was performed to identify TNFR1 knockdown in these primary human NP cells. Additionally, flow-cytometry was performed to determine transduction efficiency in human NP cells.

Functional TNFRJ Knockdown.

Functional knockdown of TNFR1 was studied by quantifying TNF-α induced NF-KB activity after CRISPRi knockdown. NF-KB activity was quantified using a firefly luciferase NF-KB reporter vector that was transduced into HEK293T cells [5]. NF-KB reporter expressing HEK293T cells were also transduced with the developed TNFRI lentiviral CRISPRi vector and cell sorted for GFP to produce a cell line expressing the TNFR1 CRISPRi system. These cells along with the non-knockdown cells were seeded at 25,000 cells/well in white opaque plates and treated with either 0 ng/ml, 150 pg/ml, 1 ng/ml, and 10 ng/ml rhTNF-α, for 24 hours (n=5 per treatment). NF-KB activity was then measured using a firefly luciferase luminescence assay (Bright-Glo, Promega). Additionally, cell number was assayed (RealTime-Glo, Promega) on a separate plate with the same experimental conditions, therefore allowing for normalization of each NF-KB luminescence signal to the number of viable cells. Luminescence for both assays was measured using a synergy HTX biotek plate reader. Activity of NF-KB is reported as a fold change relative to control and normalized by cell viability.

Statistical Analysis.

To determine if knockdown of IL1R1 and TNFR1 in HEK293T cells was statistically significant, a one-way ANOVA was conducted with Tukey post hoc. For statistical analysis of NF-KB activity, a two-way ANOVA with Tukey post hoc was conducted and a p<0.05 was considered statistically significant.

Results

CRISPRi Vector Design.

Quantitative reverse transcriptase PCR studies for both TNFR1 and IL1R1 in HEK293T cells show significant knockdown in four out of five guides for TNFR1 and two out of seven guides for IL1R1. Maximum knockdown in the guides screened was 82% for TNFRI and 67% for IL1R1 (FIG. 12A-B). Using gRNA 4 for TNFR1 with dCas9-KRAB, 55% TNFR1 knockdown was observed in NP cells but no knockdown with dCas9 alone (FIG. 13B). Transduction efficiency of TNFR1 lentiviral CRISPRi vector in human NP cells was 42%.

Functional TNFRI Knockdown.

Fold change in NF-KB activity was significantly decreased in response to TNF-α after TNFR1 CRISPRi knockdown at each TN F-α dose, demonstrating a decrease in TNFR1 induced signaling (FIG. 13). The decrease in activity was on the order of −95% for the two highest doses and returned the lowest dose to baseline levels. These results indicate a complete elimination of this deleterious signaling pathway at the most physiologically relevant dose.

Discussion

These studies show that CRISPRi knockdown of inflammatory receptors can be used to modulate the inflammatory response relevant to disc pathology. These results also show that CRISPRi can be used to significantly reduce gene expression of TNFRI and IL1R1 in HEK293T cells and TNFR1 gene expression in human NP cells (FIGS. 12 and 13). The results also show that this measured reduction in TNFR1 gene expression also results in a loss of TNFR1 signaling, as demonstrated by the significantly lower fold change in NF-KB activity in TNFR1 knockdown versus number of knockdown cells for each TNF-α dose (FIG. 14). This finding relates to disc pathology, as NF-KB signaling has been identified as a component in the degenerative process and antagonizing NF-KB activity has shown therapeutic effects in preclinical animal models. The data also shows that TNFRI CRISPRi was able to return the physiologically relevant dose (150 pg/ml) to baseline levels. Despite the 42% transduction efficiency, the CRISPRi system showed expression and activity in human primary NP cells, making their application to the disc a possibility. Methods to improve transduction efficiency in the primary human NP cells and the ability of this system to promote viable tissue formation in the inflammatory environment in the degenerative IVD can also be investigated. These data show a step in developing and applying the CRISPRi dCas9 system to disc pathology, which can be used for both gene therapy applications and tissue engineering applications targeting DOD.

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What is claimed is:
 1. A CRISPR-Cas system comprising one or more vectors comprising: a) a promoter operably linked to a nucleotide sequence encoding a CRISPR-Cas system guide RNA (gRNA); and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein the gRNA comprises: a gRNA sequence having the sequence of SEQ ID NOs: 63, 61, 62 or 64; a gRNA sequence having the sequence of SEQ ID NOs: 79, 80, 81, 82 or 83; and a gRNA sequence having the sequence of SEQ ID NOs: 85, 84, 86, 87, 88, or
 89. 2. The CRISPR-Cas system of claim 1, wherein the RNA-directed nuclease is a dCas9 protein.
 3. The CRISPR-Cas system of claim 2, wherein the Cas9 protein is codon optimized for expression in the cell.
 4. The CRISPR-Cas system of claim 1, wherein the cell is a mammalian or human cell; and/or a mesenchymal stem cell.
 5. The CRISPR-Cas system of claim 1, wherein the system is packaged into a single lentiviral, adenoviral or adeno-associated virus particle.
 6. A vector comprising: a) a promoter operably linked to a nucleotide sequence encoding a CRISPR-Cas system guide RNA (gRNA); and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease; wherein the gRNA comprises: a gRNA sequence having the sequence of SEQ ID NOs: 63, 61, 62 or 64; a gRNA sequence having the sequence of SEQ ID NOs: 79, 80, 81, 82 or 83; and a gRNA sequence having the sequence of SEQ ID NOs: 85, 84, 86, 87, 88, or
 89. 7. The vector of claim 6, wherein components a) and b) are located on the same or different vectors of the same system.
 8. The vector of claim 6, wherein the RNA-directed nuclease is a dCas9 protein.
 9. The vector of claim 6, wherein the cell is a mammalian or human cell; and/or a mesenchymal stem cell.
 10. A method of modulating expression of a gene in a cell, the method comprising: introducing into the cell CRISPR-Cas system comprising one or more vectors comprising: a) a promoter operably linked to a nucleotide sequence encoding a CRISPR-Cas system guide RNA (gRNA); and b) a regulatory element operably linked to a nucleotide sequence encoding a RNA-directed nuclease, wherein the gRNA comprises: a gRNA sequence having the sequence of SEQ ID NOs: 63, 61, 62 or 64; a gRNA sequence having the sequence of SEQ ID NOs: 79, 80, 81, 82 or 83; and a gRNA sequence having the sequence of SEQ ID NOs: 85, 84, 86, 87, 88, or
 89. 11. A pharmaceutical composition comprising the nucleic acid sequence of claim
 1. 12. The pharmaceutical composition of claim 11, wherein the composition comprises a pharmaceutically acceptable carrier.
 13. The pharmaceutical composition of claim 12, wherein the pharmaceutically acceptable carrier comprises a lipid-based or polymer-based colloid.
 14. The pharmaceutical composition of claim 11, wherein the composition is formulated for intervertebral administration.
 15. A method of treating a subject having lower back pain, the method comprising administering to the subject a therapeutically effective amount of the pharmaceutical composition of claim
 11. 16. The method of claim 15, wherein in the lower back pain is caused by degenerative disc disease.
 17. The method of claim 15, wherein the composition is administered into or adjacent to the intervertebral disc.
 18. The method of claim 15, further comprising: determining TNF, IL1, IL6, IL9, IFN-gamma, and/or IL17 levels in the subject prior to the administration step. 